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### 7 Notes written by me

• #### Metal Cutting

Files: 1

Merchant Circle Diagram.

• #### Metal Cutting(Manufacturing)

Files: 1

Estimation of Machining Time

• #### Metal Cutting(Manufacturing)

Files: 1

Manufacturing of Gears

• #### Fluid Mechanics

Files: 1

Notes On Buoyancy & Flotation.

• #### Thermodynamics And Its Laws

Files: 1

Basic Concept of Thermodynamics

• #### Thermodynamics

Files: 1

First Law of Thermodynamics.

• #### Fluid Mechanics

Files: 1

Application of Bernoulli Equation.

• ## Question: Please tell me who the poet was who had written ‘Ozymandias.’  ...

Posted in: Communicative English,Business English | Date: 08/03/2018

percy bysshe shelley

• ## Question: The oxidation number of carbon in $$CH_2O$$ is

Posted in: WBJEE | Date: 08/03/2018

0

• ## Question: What is the SI unit of surface tension?

Posted in: AMIE | Date: 08/03/2018

Newton/metre

• ## Question: What are the units of K = $$\frac {1}{4\pi\varepsilon_0 }$$?

Posted in: Physics | Date: 08/03/2018

• ## Question: The unit of permittivity of free space $$\varepsilon_0$$ is .....

Posted in: Physics | Date: 08/03/2018

• ## Question: If 0.50 mole of $$BaCl_2$$ is mixed with 0.20 mol of $$Na_3PO_4$$, the maximum n...

Posted in: WBJEE | Date: 09/03/2018

3BaCl2 + 2Na3PO4  ------------->  Ba3(PO4)2 + 6Nacl

0.5 mol           0.20 mol               x mol

First find which is the limiting reagent?

0.5/3 = 1/6          0.2/2 = 1/10

1/10 < 1/6

thus,  Na3PO4 is the limiting reagent.

Now, 1/10 = x/1

x = 0.1 mol.

(d) may be the ansr.

• ## Question: One mole of $$N_2H_4$$ loses ten moles of electrons to form a new compound Y. As...

Posted in: WBJEE | Date: 09/03/2018

Oxidation state of NItrogen in n2h4 is -2.  2(-2) + 4(+1)= 0

therefore two N makes it -4 , since they lose 10 e-  , hence total charge is +6, and since H is still +1 ,  Two N divides the +6 .

then ox state of N is +3 in the new compound Y.

• ## Question: M is molecular weight of $$KMnO_4$$. The equivalent weight of $$KMnO_4$$when it ...

Posted in: WBJEE | Date: 09/03/2018

The equivalent mass of a substance is the ratio of molecular mass to the number of electrons gained (or lost) or change in the oxidation state. That  is equivalent mass = molecular mass/number of electrons gained or lost or

= molecular mass/change in oxidation state

Here, potassium permanganate changes to potassium manganate. The relevant chemical reaction is:

Only 1 electron is gained by permanganate ion to convert to manganate ion. We can also see that the oxidation state of manganese is +7 in permanaganate ion and it changes to +6 in manganate ion. That is, the oxidation state changes by 1.

Thus, the equivalent mass = molecular mass/1 = molecular mass = M

Hence, the equivalent mass of KMnO4 is M when it converts over to K2MnO4.

• ## Question: 2.76 g of silver carbonate on being strongly heated yields a residue weighing &n...

Posted in: AIEEE | Date: 09/03/2018

Unlike other metal carbonates that usually decomposes into metal oxides liberating carbon dioxide, silver carbonate on heating decomposes into elemental silver liberating mixture of carbon dioxide and oxygen gas as

Ag2CO3 (s) 2Ag (s) + CO2 (g) + 1/2 O2 (g) MW = 276g 2 × 108 = 216 g

Hence, 2.76 g of Ag2CO3 on heating will give 216/276× 2.76 = 2.16 g Ag as residue

• ## Question: A gaseous mixture contains oxygen and nitrogen in the ratio of 1: 4 by weight. T...

Posted in: WBJEE | Date: 09/03/2018

Oxygen/Nitrogen=1/4(by weight}

Ratio of number of molecules =144×16=732

7:32 is the ratio of their no of molecules.

Hence c is the correct answer.

• ## Question: The total number of electrons in one molecule of carbon dioxide is

Posted in: AMITE | Date: 09/03/2018

Number of electrons in a molecule is equal to the sum of electrons in individual atoms in it. # electrons in an atom is equal to its atomic number.

Total in CO2 -------> 6 + (2 x 8) = 22 electrons.

• ## Question: The largest number of molecules is in

Posted in: WBJEE | Date: 09/03/2018

Number of molecules present in 36 g of water = 36/18×N A = 2N A

Number of molecules present in 28 g of CO = 28/28×N A = N A Number of molecules present in 46 g of C2H5OH = 46/46×N A = N A

Number of molecules present in 54 g of N2O5 = 54/108×N A = 0.5N A

Hence, 36 g of water contain the larges (2N A) number of molecule.

• ## Question: E, m, l and G denote energy, mass, angular momentum and gravitational constant r...

Posted in: Physics | Date: 09/03/2018

EJ2m5G2=[ML2T−2][ML2T−1]2[M5][M−1L3T−2]2

=[M0L0T0]

The dimension of EJ2m5G2 are Angle

Hence A is the correct answer.

• ## Question: The temperature of a body on Kelvin scale is found to be X K. When it is measure...

Posted in: Physics | Date: 09/03/2018

[(F – 32) / 9] = [(K – 273) / 5]

∴ F – 32 = (9/5)(K – 273)

given : Temperature on kelvin scale = xk

Temperature on Fahrenheit = xF

∴        F = K = x

∴        x – 32 = (9/5)(x – 273)

(4/5)x = 459.67

∴        x = 574.25

• ## Question: The compound $$YBa_2Cu_3O_7$$, which shows superconductivity, has copper in oxid...

Posted in: WBJEE | Date: 09/03/2018

Yttrium is exclusively trivalent (like Sc and La, and most other rare earths), Ba is exclusively divalent like other alkaline earths, (and almost all Y and Ba compounds are ionic), oxygen is nearly always divalent. The O atoms produce a charge of -14, Y produces +3, the 2 Bas produce +4; leaving +7 to be accounted for by the 3 Cus, an average valence of 7/3. So 2 of each 3 Cus must be divalent, and the third trivalent.

But, as it is not produced by methods involving use of strong oxidants, it is more likely that YBa2Cu3O7, being a solid crystalline compound, is a "non-stoichiometric" compound, with a deficiency of electrons (stabilized by the crystal structure in which there are "holes" making the Cu appear to have an average oxidation state of 7/3. The superconductivity of it would be due to these positive "holes" being able to move freely in the solid when an external potential difference is applied across it.

• ## Question: A compound was found to contain nitrogen and oxygen in the ratio 28 gm and 80 gm...

Posted in: AIEEE | Date: 09/03/2018

• ## Question: What is the SI unit of universal gas constant (R) ?

Posted in: Physics | Date: 09/03/2018

units of universal gas constant-

Value of  R in M.K.S. System

According to Avogadro’s law, the volume of one mole of a gas at NTP is 22.4 litre. Standard temperature & pressure at N.T.P. are 00C & 1 atm

P=1 atm.

V=22.4 l

n= 1 mole.

T=  2730K

R=0.0821 litre atmosphere/degree/mole.

Value of R. in C.G.S. System

If P is expressed in dyne/Cm2 & V in Cm3

P=1 atm = 76 cm. of Hg = 76×13.6×981 dyne/cm2

V= 22.4 litre = 22400 ml = 22400 cm3

n= 1 mole

T= 0+273 = 2730K

= 8.3 ×107 erg/degree/mole

= 8.3 Joule/degree/mole

Because one calorie is equivalent to 4.08×107 erg. So,

R =[ 8.3×107 erg/degree/mole ×  1calorie] /( 4.08×107 erg )

= 2 calorie/degree/mole

• ## Question: The weight of $$1 \times 10^{22}$$ molecules of $$CuSO_4 .5H_2O$$ is ..............

Posted in: AIEEE | Date: 09/03/2018

Given,  Number of molecules = 1 x 10^22 molecules  Molecular mass of CuSO4.5H2O = 249.72g/mol We know that,  1 mole of CuSO4.5H2O contains 6.023 x 10^23 molecules Therefore,  6.023 x 10^23 molecules have a mass of 249.72g

Hence, Weight of 1 × 10^22 molecules =

(249.72/6.023 ×10^23)× 1 × 10^22 = 4.146 g

• ## Question: The surface tension of a liquid is ne/70 cmdy. In MKS system its value is .....?

Posted in: Physics | Date: 09/03/2018

As,1 dyne =10^-5 Newton  , 1 cm = 10^-2 cm.

• ## Question: 3 g of a salt of molecular weight 30 is dissolved in 250 g of water. The molalit...

Posted in: AIEEE | Date: 09/03/2018

Molality=(Moles of Sloute)/(Mass of Solvent in kg)

so, (3g of salt/250 g of H2O) x (1 mole salt/30 g salt) x (1000g/1 kg) = 0.4 m

• ## Question: The total number of electrons present in 18 ml of water is ........................

Posted in: WBJEE,AIEEE | Date: 09/03/2018

We know density of water is 1 gm/cc or 1 gm/ml. So 18 ml of water contains 18 gm of water implies 1 mole of water.

By Avogadro no. 1 mole of water contains 6.023 x 10^(23) molecules of water.

But each molecule of water contains 10 electrons.

Thus 6.023 x 10^(23) molecules of water will contain 10 x 6.023 x 10^(23) electrons= 6.023 x 10^(24) electrons.

• ## Question: The set of intelligent students in a class is

Posted in: Mathematics | Date: 09/03/2018

since there is quantification of intelligency,set cannot be defined.

so,it is a null set.

Hence, A is the correct answer.

• ## Question: Any idea what to prepare for the ISC Chemistry Exam 2018?

Posted in: Chemistry | Date: 09/03/2018

Keep the following points in mind to score well in the exam:

1 For five chapters of physical chemistry, it is better to practise numerical problems on each formulae discussed in these chapters. Reasoning-type questions on crystal defects, ideal and non-ideal solutions, azeotropes, dilution and its relation with conductivity, molar conductivity, Kohlrausch law, Faraday laws, batteries and their cell reactions involved, adsorption isotherms, colloids and its properties and applications need to be mastered properly.

2 For the next four chapters involving inorganic chemistry, students have to develop understanding of concepts to be able to write balance chemical equations related to p-block and d and f block elements and draw structures of oxy acids, compounds of xenon, hydrolysis reactions involving xenon fluorides, VBT related complexes and CFT, preparation and properties of permanganate and dichromate, metal carbonyl bonding and reasoning related to metallurgy.

3 NCERT book-2 deals with organic chemistry chapters. Students must practice most organic reactions, substitution and elimination reactions of haloalkanes and haloarenes, reactions involving Grignard reagent, and mechanisms from alcohol and phenol and ethers are important.

4 The last three chapters are useful for value-based and reasoning-based questions. It is important to have a clear understanding of structures of cyclic glucose and fructose, glycosidic, peptide and phosphodiester linkages, types of protein and nucleic acid. Revise each chapter thoroughly.

• ## Question: What are the questions that can come from ‘Arms And The Man’ in the ...

Posted in: English | Date: 09/03/2018

Character sketches of the characters like Raina, Bluntschli,Sergius,Louka.

Act 1 Raina Bluntschli episode

Act 2 Sergius Louka episode

Significance of the acts.

How the anti war message is conveyed in the play

How Louka and Nicola are opportunists

Contrast between Sergius and Bluntschli

Significance of chocolate creams

Thank you.

• ## Question: Am I eligible for MCA course after graduating in bba

Posted in: BBA Subjects,MCA Subjects,BCA Subjects | Date: 09/03/2018

es, you are eligible for MCA after completing BBA.

MCA-MASTER OF COMPUTER APPLICATION is a post graduation degree course of two years duration having four semesters.

The candidate having completed Graduation in any discipline with at least 60% marks is eligible to apply for MCA course. Apart from this the candidate should have Mathematics in 10+2 level or in Graduation. There is no age limit for application for MCA course.

As you are a Graduate in Business Administration you can apply for MCA. Some reputed Institution conducts entrance exam for admission to MCA course.

• ## Question: What Are the Main poses that you need to have in your walk cycle to get good mov...

Posted in: Animation | Date: 09/03/2018

A walk cycle can be described by four distinct poses:

CONTACT,DOWN,PASSING and HIGH-POINT.

These four poses and a handful of inbetween drawings constitute a walk cycle. The single most important frame of the four is the contact pose. Once you draw it you have already determined 80% of the rest of your walk. If you make a mistake on your contact pose, it can be very difficult to correct later on. Therefore: pay close attention now and save yourself a world of pain.

• ## Question: One of the following is a difference between a run cycle and a walk cycle:

Posted in: Animation | Date: 09/03/2018

Always walk, one foot remains on the ground. Only one foot leaves the ground at a time. But in a run cycle, at some point, will either foot contact with the ground.

• ## Question: Please tell me the general sequence of a Prime Number.

Posted in: Mathematics | Date: 09/03/2018

prime numbers are those who divide  by  one and the number itself.

i.e. 2,3 ,5 ,7,11,13,........43,47,.........

• ## Question: How hormones are transported through the body?

Posted in: Biology | Date: 09/03/2018

One of the functions of blood is to transport dissolved substances, including hormones, around the body. Hormones are chemical substances that help to regulate processes in the body. Insulin is one such hormone, regulating the level of glucose in the blood.

• ## Question: What gland controls blood sugar levels?

Posted in: Biology | Date: 09/03/2018

Functioning as an endocrine gland, the pancreas secretes the hormones insulin and glucagon to control blood sugar levels throughout the day. Both of these diverse functions are vital to the body's survival.

• ## Question: Which hormone is a peptide?

Posted in: Biology | Date: 09/03/2018

Peptide hormone. Like all peptides and proteins, peptide hormones and protein hormones are synthesized in cells from amino acids according to mRNA transcripts, which are synthesized from DNA templates inside the cell nucleus.

• ## Question: Explain about Bursting Strength Testing Method?

Posted in: Fashion Designing | Date: 09/03/2018

Bursting strength is a method of measuring strength in which the material is stressed in all the directions at the same time and is therefore more suitable for materials such as knitted fabrics, lace or non-woven.

Fabrics used in parachute, filters, sacks and nets are simultaneously stressed in all the directions during service. In service, a fabric is more likely to fail by bursting than by a straight tensile fracture;

Example: The stress present at elbows and knees of clothing. During a test a fabric fails across the direction which has the lowest breaking extension

• ## Question: How does soil erosion affect people's lives?

Posted in: Geography | Date: 09/03/2018

"Soil erosion is second only to population growth as the biggest environmental problem the world faces," said David Pimentel, professor of ecology at Cornell. "Yet, the problem, which is growing ever more critical, is being ignored because who gets excited about dirt?"

Plenty of people should be, stressed Pimentel, whose study on the food and environmental threat of soil erosion is published in a recent issue of the Journal of the Environment, Development and Sustainability (Vol. 8, 2006).

"Erosion is a slow and insidious process," stressed Pimentel. "Yet, controlling soil erosion is really quite simple: The soil can be protected with cover crops when the land is not being used to grow crops."

Other ways to reduce erosion include reducing the need for people in developing countries to clear forests for agriculture, overgraze their cattle and remove crop residues for cooking fuel.

The vast majority -- 99.7 percent -- of human food comes from cropland, which is shrinking by more than 10 million hectares (almost 37,000 square miles) a year due to soil erosion, Pimentel reports, while more people than ever -- more than 3.7 billion people -- are malnourished.

"Erosion is one of those problems that nickels and dimes you to death: One rainstorm can wash away 1 mm (.04 inches) of dirt. It doesn't sound like much, but when you consider a hectare (2.5 acres), it would take 13 tons of topsoil -- or 20 years if left to natural processes -- to replace that loss," Pimentel said. "And that kind of loss occurs year after year by wind and rain around the world."

• ## Question: Describe about Tensile Strength Testing Method?

Posted in: Fashion Study | Date: 09/03/2018

A tensile test, also known as tension test, is probably the most fundamental type of mechanical test you can perform on material. Tensile tests are simple, relatively inexpensive, and fully standardized. By pulling on something, you will very quickly determine how the material will react to forces being applied in tension. As the material is being pulled, you will find its strength along with how much it will elongate.

For most tensile testing of materials, you will notice that in the initial portion of the test, the relationship between the applied force, or load, and the elongation the specimen exhibits is linear. In this linear region, the line obeys the relationship defined as "Hooke's Law" where the ratio of stress to strain is a constant, or . E is the slope of the line in this region where stress (σ) is proportional to strain (ε) and is called the "Modulus of Elasticity" or "Young's Modulus".

• ## Question: Write short notes an Martindale Abration Tester?

Posted in: Fashion Designing | Date: 09/03/2018

Description:

For the control of abrasion and pilling on almost all kind of woven and knitted fabrics, non-wovens, socks, gloves, natural and artificial leather, both dry and wet samples. Extremely versatile, accurate, silent, vibration free, 100% made in Italy. Supplied with a kit of top quality consumables complete with traceable certificate

Testing procedure :

In conformity with the International Standards, the testing fabric specimen is brought into contact and rubbed against a Standard reference fabric (abrasion test) or against the same type of specimen or against a Standard felt (Pilling test), following a predetermined number of specific rotary motions known as “Lissajous figure” paths. Basically, the abrasion test end point is reached once the operator detects visually the first two broken threads on the tested fabric specimen, whereas the Pilling test is accomplished by observing (after e certain number of laps), the created pill effect (surface fuzzing) on the fabric specimen and comparing it with the special Standard photographs. For Pilling tests according to ISO EN and EMPA (referred also as “Swiss Pilling”) Standards, a particular sample holder is required (with special dimensions and weight) and special photograph Standards: EMPA 991 for woven fabrics and EMPA 992 for knits. Other special International Standards call for specific abrasion tests using Standardised sandpaper.

• ## Question: The resistance of a conductivity cell containing 0.001M KCl solution at 298 K is...

Posted in: Chemistry | Date: 09/03/2018

Given that ,

Conductivity of the cell ,

κ = 0.146 × 10−3 S/cm

Resistance of the cell , R = 1500 Ω

Formula of cell constant

Cell constant = κ × R

Plug the values we get

= 0.146 × 10−3 × 1500

= 0.219 cm−1

• ## Question: Briefly explain in-vitro fertilization.

Posted in: Biology | Date: 09/03/2018

In Vitro Fertilization is an assisted reproductive technology (ART) commonly referred to as IVF. IVF is the process of fertilization by extracting eggs, retrieving a sperm sample, and then manually combining an egg and sperm in a laboratory dish. The embryo(s) is then transferred to the uterus.

• ## Question: Write a short note on crop rotation.

Posted in: Biology | Date: 09/03/2018

Crop rotation is the practice of growing a series of dissimilar types of crops in the same area in sequential seasons for various benefits such as to avoid the build up of pathogens and pests that often occurs when one species is continuously cropped. Crop rotation also seeks to balance the fertility demands of various crops to avoid excessive depletion of soil nutrients. A traditional element of crop rotation is the replenishment of nitrogen through the use of green manure in sequence with cereals and other crops. It is one component of polyculture. Crop rotation can also improve soil structure and fertility by alternating deep-rooted and shallow-rooted plants.  Crop rotation avoids a decrease in soil fertility, as growing the same crop in the same place for many years in a row disproportionately depletes the soil of certain nutrients. With rotation, a crop that leaches the soil of one kind of nutrient is followed during the next growing season by a dissimilar crop that returns that nutrient to the soil or draws a different ratio of nutrients, for example, rice followed by cotton. By crop rotation farmers can keep their fields under continuous production, without the need to let them lie fallow, and reducing the need for artificial fertilizers, both of which can be expensive. Rotating crops adds nutrients to the soil. Legumes, plants of the family Fabaceae, for instance, have nodules on their roots which contain nitrogen-fixing bacteria. It therefore makes good sense agriculturally to alternate them with cereals (family Poaceae) and other plants that require nitrates. An extremely common modern crop rotation is alternating soybeans and maize (corn). In subsistence farming, it also makes good nutritional sense to grow beans and grain at the same time in different fields.  Crop rotation is a type of cultural control that is also used to control pests and diseases that can become established in the soil over time. The changing of crops in a sequence tends to decrease the population level of pests. Plants within the same taxonomic family tend to have similar pests and pathogens. By regularly changing the planting location, the pest cycles can be broken or limited. For example, root-knot nematode is a serious problem for some plants in warm climates and sandy soils, where it slowly builds up to high levels in the soil, and can severely damage plant productivity by cutting off circulation from the plant roots. Growing a crop that is not a host for root-knot nematode for one season greatly reduces the level of the nematode in the soil, thus making it possible to grow a susceptible crop the following season without needing soil fumigation.

• ## Question: Explain budding with the help of suitable example.

Posted in: Biology | Date: 09/03/2018

Budding is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. ... The new organism remains attached as it grows, separating from the parent organism only when it is mature, leaving behind scar tissue.

The plants which can not be propagated by other vegetative means viz. cutting, layers, or division can be multiplied, preserved and perpetuated by grafting and budding.

• ## Question: Write a brief note on fertilizers.

Posted in: Biology | Date: 09/03/2018

Manures are not able to supply the required quantities of the essential plant nutrients to the soil. So they are to be supplemented with chemical fertilizers. Fertilizers are chemical compounds, which are applied to the soil to increase the supply of one or more of the essential nutrients such as nitrogen, phosphorus or potash. Fertilizers are generally inorganic materials and contain these elements in the form of soluble chemical compounds. Fertilizers are usually classified according to the particular plant nutrient, which forms their principal constituent. Chemical fertilizers may be classified into the following types:

1. Nitrogenous fertilizers

2. Phosphatic fertilizers

3. Potassic fertilizers

4. Compound fertilizers

5. Mixed fertilizers

• ## Question: The temperature of a body on Kelvin scale is found to be X K. When it is measure...

Posted in: Physics | Date: 09/03/2018

[(F – 32) / 9] = [(K – 273) / 5]

∴ F – 32 = (9/5)(K – 273)

Given : Temperature on kelvin scale = xk

Temperature on Fahrenheit = xF

∴        F = K = x

∴        x – 32 = (9/5)(x – 273)

(4/5)x = 459.67

∴        x = 574.25

• ## Question: How many of electrons are present in 18 ml of water? Help me to solve the p...

Posted in: Chemistry | Date: 09/03/2018

Here we will use the the concept of density of water = 1g/cc D=M/V 1 g/ml = M/18 ml M= 18 g moles of water = mass/molar mass = 18/18 = 1 1 mole of water contains = NA molecules total electrons in water = 2(H) + 8(O) = 10 1 molecule of water contains = 10 electrons 1 mole water contains = 10 * NA electrons NA = Avogadro’s number

• ## Question: Silver crystallises in fcc lattice. If edge length of the cell is $$4.07 \times ... Posted in: Chemistry | Date: 09/03/2018 ### Answer: From the equation, density = ZxM/a^3 x N0, we get M = ρ x a^3 x N0/Z …………………………………1 Placing the values in equation 1, WE GET M= 10.5 x (4.077 x10^-8)^3 x 6.022 x 1023/4 = 107.1 g/mol = Therefore, atomic mass of silver = 107.1 g/mol • ## Question: A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 &Omeg... Posted in: Physics | Date: 09/03/2018 ### Answer: PD,V= 9V Resistance,R=R1+R2+R3+R4 =0.2+0.3+0.4+0.5+12=13.4ohm I =V/R = 9/13.4 = 0.67A Resistors are connected in series therefore the current flowing through each will be equal to 0.67 A • ## Question: When a 12 V battery is connected across an unknown resistor, there is a current ... Posted in: Physics | Date: 09/03/2018 ### Answer: We have potential difference (V) = 12V Electric current (I)=2.5 mA= 2.4×10-3 According to Ohm’s Law (V) = IR Or R = V/I R=12/12.5^10^-3 =4.8x10^3 ohm • ## Question: A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution... Posted in: Chemistry | Date: 09/03/2018 ### Answer: According to question, 300g of 25% solution contains solute = (300 x 25) / 100 = 75g of solute 400g of 40% solution contains solute = (400 x 40) / 100 = 160g of solute Total solute = 75 + 160 = 235g As given in the question, total solution =300 + 400 = 700g Percentage of solute in the final solution = (235 x100) / 700 = 33.5% Percentage of water in the final solution = 100 - 33.5 = 66.5% • ## Question: Write equations for the reactions of (i) iron with steam (ii) calcium and pota... Posted in: Chemistry | Date: 09/03/2018 ### Answer: (i) 3Fe(s) + 4H2O(g) → Fe3O4 + 4H2 Iron Steam Iron (II, III) oxide (ii) Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g) + Heat Calcium hydroxide K(s) + 2H2O(l) → 2KOH(aq) + H2(g) + Heat • ## Question: You have two solutions, A and B. The pH of solution A is 6 and pH of solution B ... Posted in: Chemistry | Date: 09/03/2018 ### Answer: The pH value of a solution varies from 0 to 14. The pH value is 0 for a very strong acid and the pH value is 14 for a very strong base. The pH value is 7 for a neutral solution. Hence A is acidic and B is basic in nature. The concentration of hydrogen ion decreases from pH value of 0 to 14 therefore A has more hydrogen ion concentration. • ## Question: If a current of 0.5 ampere flows through a metallic wire for 2 hours, then how m... Posted in: Chemistry | Date: 09/03/2018 ### Answer: Current, I = 0.5 A Time, t = 2 hours Convert in sec we get Time, t = 2 × 60 × 60 s = 7200 s Use formula, Charge Q = It Plug the values we get = 0.5 A × 7200 s = 3600 Coulombs Number of electrons = total charge / charge on 1 electrons = 3600/(1.6 ×10 19) =2.25 × 1022 electrons • ## Question: Write a short note on plasma membrane. Posted in: Biology | Date: 09/03/2018 ### Answer: Plasma Membrane Definition The plasma membrane of a cell is a network of lipids and proteins that forms the boundary between a cell’s contents and the outside of the cell. It is also simply called the cell membrane. The main function of the plasma membrane is to protect the cell from its surrounding environment. It is semi-permeable and regulates the materials that enter and exit the cell. The cells of all living things have plasma membranes. he plasma membrane surrounds all cells and physically separates the cytoplasm, which is the material that makes up the cell, from the extracellular fluid outside the cell. This protects all the components of the cell from the outside environment and allows separate activities to occur inside and outside the cell. The plasma membrane provides structural support to the cell. It tethers the cytoskeleton, which is a network of protein filaments inside the cell that hold all the parts of the cell in place. This gives the cell its shape. Certain organisms such as plants and fungi have a cell wall in addition to the membrane. The cell wall is composed of molecules such as cellulose. It provides additional support to the cell, and it is why plant cells do not burst like animal cells do if too much water diffuses into them. • ## Question: Please tell me which chapters to prepare for English Literature, ISC 2018. Posted in: English | Date: 09/03/2018 ### Answer: Short stories: 1)The Legend of Sleepy Hollow(bound to come this year but my personal recommendation is that please do not attempt this highly irritating story ,as it is ,you will lose your mind reading this one) 2)A Real Durwan 3)The Lumber Room 4)Lamb to the slaughter Collection of poems: 1)Dulce et Decorum est (bound to come this year and my personal recommendation is that please do attempt this one as it is a small poem and also very nice(my favourite!)) 2)Mending wall 3)Do not go gentle into the good night(bound to come) 4)Father returning home • ## Question: What are the negative effects of soil pollution? Posted in: Geography | Date: 09/03/2018 ### Answer: The Effects of Soil Pollution on Humans. ... The chemicals may be foreign to the area, or they may be naturally occurring materials that pollute the soil by being present in dangerously high amounts. Soil pollution can have a number of harmful effects on human health. Soil erosion is a naturally occurring process that affects all land forms. In agriculture,soil erosion refers to the wearing away of a field's topsoil by the natural physical forces of water and wind or through forces associated with farming activities such as tillage. • ## Question: How can we reduce water pollution? Posted in: Geography | Date: 09/03/2018 ### Answer: • DO NOT pour fat from cooking or any other type of fat, oil, or grease down the sink. ... • DO NOT dispose of household chemicals or cleaning agents down the sink or toilet. ... • DO NOT flush pills, liquid or powder medications or drugs down the toilet. ... • Avoid using the toilet as a wastebasket. ... • Avoid using a garbage disposal. • ## Question: How do human activities affect our soil? Posted in: Biology | Date: 09/03/2018 ### Answer: The way people use land can affect the levels of nutrients and pollution in soil. Any activity that exposes soil to wind and rain can lead to soil loss. Farming, construction and development, and mining are among the main activities that impact soil resources. ... Over time, many farming practices lead to the loss of soil. • ## Question: Explain about Wet & Dry Bulb Hygrometer? Posted in: Fashion Designing | Date: 09/03/2018 ### Answer: Psychrometer (wet- and dry-bulb hygrometer) Hygrometerusing evaporative cooling as a measure of humidity. Consists of two thermometers, one of these has a dry bulb, and the bulb of the second is kept wet. Evaporation at the wet bulb lowers the temperature so this thermometer usually displays a lower temperature. The wet bulb thermometer is covered with a damp cloth dipped in water. To use a hygrometer: fill the water bottle and screw it on to the instrument. hang the hygrometer (by the loop at the top) on a wall or a tree, for instance, for at least five to 10 minutes before taking the measurements. • ## Question: Why soil is important for us? Posted in: Biology | Date: 09/03/2018 ### Answer: Soil is a vital part of the natural environment. It is just as important as plants, animals, rocks, landforms, lochs and rivers. It influences the distribution of plant species and provides a habitat for a wide range of organisms. It controls the flow of water and chemical substances between the atmosphere and the earth, and acts as both a source and store for gases (like oxygen and carbon dioxide) in the atmosphere. Soils not only reflect natural processes but also record human activities both at present and in the past. They are therefore part of our cultural heritage. The modification of soils for agriculture and the burial of archaeological remains are good examples of this. Soil, together with the plant and animal life it supports, the rock on which it develops, its position in the landscape and the climate it experiences, form an amazingly intricate natural system – more powerful and complex than any machine that man has created. Soil may look still and lifeless, but this impression couldn’t be further from the truth. It is constantly changing and developing through time. Soil is always responding to changes in environmental factors, along with the influences of man and land use. Some changes in the soil will be of short duration and reversible, others will be a permanent feature of soil development. • ## Question: What are the side effects of hormonal imbalance? Posted in: Biology | Date: 09/03/2018 ### Answer: Hormonal imbalances trigger not only fat storage andweight gain, it also triggers many other nasty symptoms like PMS, acne, painful breasts, migraines, cellulite, loss of libido, a disrupted monthly cycle, menopausal issues, and burn-outs • ## Question: Can you get pregnant if you have a hormonal imbalance? Posted in: Biology | Date: 09/03/2018 ### Answer: If you are trying to conceive, hormonal imbalances can make it extremely difficult to get pregnant. ... One of the most common hormonal imbalances that is present in women who have fertility issues is an imbalance of the hormone progesterone. • ## Question: What are the four types of hormones? Posted in: Biology | Date: 09/03/2018 ### Answer: • >Steroid hormones – these are made from cholesterol. ... • >Eicosanoids: these are lipid hormones – hormones made from lipids, kinds of fats. ... • >Amino acid derived. ... • >Peptides, polypeptides and proteins – small peptide hormones include TRH and vasopressin. • ## Question: What are the symptoms of hormonal imbalance? Posted in: Biology | Date: 09/03/2018 ### Answer: • Infertility and irregular periods. • Weight gain or weight loss (that's unexplained and not due to intentional changes in your diet) • Depression and anxiety. • Fatigue. • Insomnia. • Low libido. • Changes in appetite. • Digestive issues. • ## Question: What do you mean by hormones? Posted in: Biology | Date: 09/03/2018 ### Answer: a regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action. • a synthetic substance with a similar effect to that of an animal or plant hormone. • a person's sex hormones as held to influence behaviour or mood. • ## Question: What is dry ice? Why is it called as dry ice? Posted in: Physics | Date: 09/03/2018 ### Answer: Dry Ice is the common name for solid carbon dioxide (CO2). It gets this name because it does not melt into a liquid when heated; instead, it changes directly into a gas (This process is known as sublimation). When dry ice is warmed above -110° F, it changes from solid dry ice straight back to carbon dioxide gas. Since it never passes through the liquid phase, it's called dry ice. • ## Question: What is sustainable development ? Posted in: Geography | Date: 09/03/2018 ### Answer: Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. • ## Question: What is hydrosphere? Posted in: Geography | Date: 09/03/2018 ### Answer: The hydrosphere is the combined mass of water found on, under, and above the surface of a planet, minor planet or natural satellite. It has been estimated that there are 1386 million cubic kilometers of water on Earth. This includes water in liquid and frozen forms in groundwater, oceans, lakes and streams. • ## Question: What are the negative side effects of wind power? Posted in: Chemistry | Date: 09/03/2018 ### Answer: Although wind power plants have relatively little impact on the environment compared to fossil fuel power plants, concerns have been raised over the noise produced by the rotor blades, visual impacts, and deaths of birds and bats that fly into the rotors (avian/bat mortality). • ## Question: What is the pros and cons of wind power? Posted in: Chemistry | Date: 09/03/2018 ### Answer: Advantages and disadvantages. Wind is a renewable energy resource and there are no fuel costs. No harmful polluting gases are produced. On the other hand, wind farms are noisy and may spoil the view for people living near them. • ## Question: What is a magnitude of a vector? Posted in: Physics | Date: 09/03/2018 ### Answer: The magnitude of a vector is the length of thevector. The magnitude of the vector is denoted as ∥ a ∥ . See the introduction tovectors for more about the magnitude of a vecto • ## Question: What are the pros and cons of nuclear fission? Posted in: Chemistry | Date: 09/03/2018 ### Answer: Pros of nuclear fusion • Clean energy. No greenhouse gases. • Virtually limitless fuel available. (The deuterium can be distilled from seawater and the tritium can be “bred” in the reactor.) • No chain reaction. Easier to control or stop than fission. • Little or no nuclear waste. ... • Very low fuel cost. Cons: Like fossil fuels, nuclear fuels are non-renewable energyresources. And if there is an accident, large amounts of radioactive material could be released into the environment. In addition, nuclear waste remains radioactive and is hazardous to health for thousands of years • ## Question: Why wind turbines are bad? Posted in: Chemistry | Date: 09/03/2018 ### Answer: Some health effects are quantifiable, while others are complex and harder to quantify, the assessment discovered. At certain decibel levels, wind farm noise can disturb sleep and trigger stress. ... The health authority report also considered visual effects such as shadow flicker, caused by rotating turbine blades • ## Question: How do you find the magnitude of a vector? Posted in: Physics | Date: 09/03/2018 ### Answer: Draw a vector triangle. When you draw the horizontal and vertical components, you end up with a right triangle. The magnitude of the vector is equal to the hypotenuse of the triangle so you can use the Pythagorean theorem to calculate it. Rearrange the Pythagorean theorem to calculate the magnitude. • ## Question: Find the number of ways of selecting 9 balls from 6 red balls, 5 white balls and... Posted in: Mathematics | Date: 11/03/2018 ### Answer: The number of ways of selecting 3 red balls out of 6 red balls =6C3 The number of ways of selecting 3 white balls out of 5 white balls =5C3 The number of ways of selecting 3 blue balls out of 5 blue balls =5C3 The number of ways of selecting 3 balls of each colour 6C3×5C3×5C3=6C3×5C2×5C2 ⇒6×5×41×2×3×5.41×2×5.41.2 ⇒20×10×10 ⇒2000 • ## Question: What is the solution of \(2x^2 + x + 2 = 0$$

Posted in: Mathematics | Date: 11/03/2018

Use the quadratic formula to find the solutions.

(−b±√b2−4(ac))/2a

Substitute the values a=2, b=2, and c=2, into the quadratic formula and solve for xx.

(−2±√22−4⋅(2⋅2))/2⋅2

Simplify.

x=(−1±√-12)/2

The result can be shown in here,

x=(−1±√-12)/2

• ## Question: A 60 μF capacitor is connected to a 110 V, 60 Hz AC supply. Determine the rms...

Posted in: Physics | Date: 11/03/2018

Given that , Capacitance of the  capacitor in the circuit , C = 60 μ F = 60 × 10 – 6 F

source voltage, V = 110 V

Frequency of the source , ν = 60 Hz

à  Angular frequency, ω = 2πν

Capacitive reactance in the circuit :

We know that ,

à  XC=1ωC=12πνC=12π×60×60×10–6Ω

Rms value of current is given as :

à  I=VXC=2202π×60×60×10–6=2.49A

Therefore, the rms current is calculated as 2.49 A.

• ## Question: A radio can tune into any station in the 7.5 MHz to 12 MHz band. What is the cor...

Posted in: Physics | Date: 11/03/2018

A radio can tune to minimum frequency, ν1 = 7.5 MHz= 7.5 × 10^6 Hz

Maximum frequency, ν2 = 12 MHz = 12 × 10^6 Hz

Speed of light, c = 3 × 10^8 m/s

Corresponding wavelength for ν1 can be calculated as:

λ1 = c/ν1=3 × 10^8 m/s/7.5 × 10^6 Hz=40 m

Corresponding wavelength for ν2 can be calculated as:

λ2= c/ν2=3 × 10^8 m/s/12 × 10^6 Hz=25 m

Thus, the wavelength band of the radio is 40 m to 25 m.

• ## Question: Explain the structure of a plough.

Posted in: Biology | Date: 11/03/2018

A Plough or Plow is an Agricultural Implement which is used to cut the soil and make it suitable for the process called seed sowing.

Before sowing the seeds into the field, it is paramount to make the field suitable.

To accomplish this, different types of ploughs are used nowadays.

Types of Ploughs

There are different types of Ploughs available to match various types of soil structures. These different types are listed below:

• Mould Board Plough
• Disc Type Plough
• Rotary Plough
• Chisel or sub surface Plough
• Sub Soiler Plough

What is the Advantage of using Plough? The major reasons are listed below:

• The first reason is to accomplish deeper seed level for efficient penetration.
• It adds more humus and fertility to the soil by covering vegetation and minerals.
• It destroys the unwanted weeds.
• It gives the soil the condition to breathe easily and air can easily pass through the soil.
• The seeds are able to establish good contact with the soil.
• The insects and their eggs are destroyed.
• The surface reaches to such a condition in which the erosion by wind is a rare possibility.

• ## Question: At room temperature (27.0$$^0$$C) the resistance of a heating element is 100$$\O... Posted in: Physics | Date: 11/03/2018 ### Answer: R1 = 100 Ω , R2 = 117 Ω α = 1.70 × 10–4 °C–1 By formula , R2 = R1 [1 + α(t2 − t1 )] R2 − R1 = R1 α(t2 − t1 ) 117 − 100 = 100 x 1.70 × 10–4( t2 − 27 ) On Solving , t2 = 1027 °C • ## Question: A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one... Posted in: Physics | Date: 11/03/2018 ### Answer: since, Nø= Mi= Ø {Ø= flux linkage} M-Mutual Inductance ∆i -current in the coil =>. ∆Ø = M∆i= 1.5×20= 30 Wb • ## Question: What secretes hormones? Posted in: Biology | Date: 11/03/2018 ### Answer: The anterior pituitary gland produces the following hormones and releases them into the bloodstream: adrenocorticotropic hormone, which stimulates the adrenal glands to secrete steroid hormones, principally cortisol. growth hormone, which regulates growth, metabolism and body composition. • ## Question: Write about Fibre Maturity? Posted in: Fashion Designing | Date: 11/03/2018 ### Answer: The cotton fiber consists of cell wall and lumen. The maturity index is dependent upon the thickness of this cell wall. Schenek [1]suggests that a fiber is to be considered as mature when the cell wall of the moisture-swollen fi ber represents 50-80% of the round cross-section, as immature when it represents 30-45%, and as dead when it represents less than 25%. Since some 5% immature fibers are present even in a fully matured boll, cotton stock without immature fibers is unimaginable: the quantity is the issue. ITMFrecommended the Fiber Maturity Tester FMT for cotton maturity determination. Measurement by FMT gives the Maturity Index (MI) • ## Question: Explain in Knowles Balance? Posted in: Fashion Study | Date: 11/03/2018 ### Answer: Knowles' balanced armature technology drives all modern hearing aids and the choice for today’s highly personal, portable, in-ear listening experience. This technology enables the design of compact components with high output power and can be widely adapted and finely tuned to meet the performance demands of specific receiver and speaker applications. For hearing aids, Knowles offers individually crafted balanced armature receivers and speakers featuring proprietary enhancements such as Pantograph™ higher audio output, Ferrofluid™ damping, D-Amp™ power management, and Vibration Isolation™. For mobile electronic devices, our balanced armature technology offers you the capacity to create customized audio performance that is unique to your product or brand. A portable music player, smartphone, or earphones can be given its own “sound” by designing precise audio characteristics into the produc • ## Question: Can hormonal imbalance be treated? Posted in: Biology | Date: 11/03/2018 ### Answer: Bioidentical Hormones. One type of hormonal imbalance treatment is bioidenticalhormone replacement therapy. ... If there is a deficiency or imbalance, BHRT is recommended to safely balance hormone levels. Restoring hormone balance canprovide greater protection from chronic diseases and alleviate menopausal symptoms. Various treatments, including natural therapies, medication and lifestyle changes, may be successful in addressing hormonal imbalances. Perhaps the most common medical treatment of hormonal imbalance is the prescription of bioidentical or synthetic hormones. This is known as hormone replacement therapy. • ## Question: How do I balance my hormones? Posted in: Biology | Date: 11/03/2018 ### Answer: Eat Enough Healthy Fats. ... Limit the Caffeine. ... Avoid Harmful Chemicals. ... Prioritize Sleep. ... Supplement Wisely. ... Exercise The Right Way. ... Consider Adding Herbs. ... Support Digestive Health. • ## Question: Why are human resources important? Posted in: Geography | Date: 11/03/2018 ### Answer: Human Resource Management deals with issues related to compensation, performance management, organisation development, safety, wellness, benefits, employee motivation, training and others. HRM plays a strategic role in managing people and the workplace culture and environment HR development is extremely important because organizations recognize that any value added to an employee is value added to the organization, and employees are eager for the opportunities to develop their skills and add value to their companies • ## Question: What is resource conservation? Posted in: Geography | Date: 11/03/2018 ### Answer: Conservation is an ethic of resource use, allocation, and protection. Its primary focus is upon maintaining the health of the natural world, its fisheries, habitats, and biological diversity. Natural Resources Conservation Service (NRCS), formerly known as the Soil Conservation Service (SCS) is an agency of the United States Department of Agriculture (USDA) that provides technical assistance to farmers and other private landowners and managers. • ## Question: What are hormones? Write any three function of hormones. Posted in: Biology | Date: 11/03/2018 ### Answer: Hormones are actually tiny chemical messengers located inside of your body. They are unable to be seen with the human eye and travel throughout the internal superhighway - otherwise known as the bloodstream - to all of your body's organs and tissues. Different hormones perform specific roles inside of your body. Some of these hormones work quickly to start or stop a process, and some will continually work over the course of a long period of time to perform their necessary jobs. Some of these jobs include the body's growth and development, metabolism (or production of energy), sexual function and reproduction. Endocrine gland Hormone Main tissues acted on by hormone Parathyroid glands Parathyroid hormone (PTH)Kidney, Bone cells Calcitonin Kidney, Bone cells Adrenal cortex Cortisol Most tissues Aldosterone Kidney • ## Question: Which gas plants use to make their food? Posted in: Geography | Date: 11/03/2018 ### Answer: The leaves contain a pigment called chlorophyll, which colors the leaves green. Chlorophyll can make food the plant can use from carbon dioxide, water, nutrients, and energy from sunlight. This process is called photosynthesis. During the process ofphotosynthesis, plants release oxygen into the air. • ## Question: What is a population pyramid? Posted in: Geography | Date: 11/03/2018 ### Answer: A population pyramid is a tool used in demography to study the changes in population over time. It is a horizontal compound bar graph. The horizontal axis shows the percent of the popualtion (male or female). The vertical axis shows the population by age groups (usually 5 years intervals). A population pyramid represents the age-sex structure of the population which is dependent on the birth and death rates of the population over time. It is a visual representation of the important demographic events over the past 80 years in a particular population. Changes can be readily seen in the graph such as the impacts of immigration/emigration, wars and famines, and changes in birth • ## Question: Why is dot product of two vectors scalar? Posted in: Physics | Date: 11/03/2018 ### Answer: In mathematics, the dot product or scalar product is an algebraic operation that takes two equal-length sequences of numbers (usually coordinate vectors) and returns a single number. ... Geometrically, it is the product of the Euclidean magnitudes of the two vectors and the cosine of the angle between them. • ## Question: What is the difference between biomass and biogas? Posted in: Chemistry | Date: 11/03/2018 ### Answer: Biomass is typically a ‘primary’ form of biofuel. Essentially created by taking organic matter and burning it for energy, it’s a simple yet effective way of producing energy. For as long as humans have been burning wood to heat their food and homes, they have been using biomass fuel. For instance, the biomass fuels we produce at Eco come from wood cuttings created by local foresters, tree surgeons and landscapers. Any wood that’s too large to become compost anytime soon, is turned into biomass fuel to create power. Biomass can come as a waste product, like ours, or it can be grown with the specific purpose of becoming biomass fuel. Crops such as sugarcane and corn starch can be grown with the intention of the fermenting its sugars to produce bioethanol, an alcohol fuel which can be used directly or as an additive to fossil fuels. Biogas is derived from organic, living matter just as biomass is. However, usually it’s harvested by processing in such a way which encourages microorganisms to digest the organic material in a process that produces gas as a result. This process is what’s known as anaerobic digestion and the complete process of how this produces gas can be found in our previous blog, here. The anaerobic digestion process occurs naturally with waste at landfill due to the lack of oxygen able to access the compacted underground waste. This digestion process produces primarily methane and carbon dioxide. Methane is said to be up to 30 times more damaging as a greenhouse has than Co2. With biogas, instead of allowing this harmful methane to escape into the atmosphere and contribute to the greenhouse effect, we harness it in our anaerobic digestion facility. We then take the methane produced and burn it to produce heat, electricity and carbon dioxide, a gas a fraction as harmful to the environment • ## Question: What is the difference between the biodiesel and biofuel? Posted in: Chemistry | Date: 11/03/2018 ### Answer: Biodiesel is made from vegetable oils (palm oil, soybean oil) and animal fat. Biofuels are made from components other than petroleum-derived products such as human and animal wastes, landfill gases, agricultural, and industrial wastes, etc. • The resources for biofuel production are abundant in everywhere compared to the biodiesel production. However, compared to the fossil fuel production, resources are more available for both bio fuel and biodiesel production. • Biodiesel is non-toxic and biodegradable, but some of the biofuels contain toxic gases. • There are various impacts of the petroleum-based industries such as social, economic, environmental, cultural, and medical. However, the impact of the biodiesels and biofuel is comparatively less. • ## Question: What are the advantages and disadvantages of biomass energy? Posted in: Chemistry | Date: 11/03/2018 ### Answer: Pros of Biomass Energy 1. Renewable: Biomass energy is a renewable resource. The principal positive about biomass energy is that it creates power by utilizing renewable assets. These assets may be wood waste, tree buildup, handled wood pellets or urban waste. As a rule, biomass energy plants utilize leftover wood that comes from existing logging or sawmill ventures. 2. Dependency on Fossil Fuels is Reduced: It replaces other fuel sources. In all cases, the fuel might be immediately replaced. By utilizing natural materials to deliver power, there is less interest for power created by non-renewable assets, for example, coal and gas. The entire purpose of utilizing renewable energy is to facilitate the reliance on sources that are harming nature’s domain in such a large number of ways. 3. Carbon Neutral: It doesn’t produce carbon. The distinction between using biomass fuel rather than coal or gas is that the carbon that is discharged was already part of nature because of the plant. At the point when coal or gas is utilized it is expelled starting from the earliest stage it has been sequestered for a large number of years. 4. Widely Available: Biomass energy is widely available all over the world. Organic waste in the form of dead leaves, grass and trees, animal carcasses are available in abundance and can be used to produce biomass energy. This in another way is good as the amount of waste that could have gone to landfills can be used as a source of energy. As long as organic matter from plants and animals is going to exist, we are never going to run out of biomass energy. 5. Can be Used in Many Forms: Biomass can be used to create different products from different forms of organic matter. It can be used to produce methane gas, biodiesel and other biofuels. It can also be used directly as heat or to generate electricity using a steam turbine. 6. Helps Reduce Waste: It helps with waste management. Consistently we create huge amounts of solid waste. This waste involves biodegradable waste, recyclable waste, along with dangerous toxic waste. Biomass energy uses this waste so that it’s no longer sitting in landfills. Cons of Biomass Energy 1. Not Totally Clean When Burned: The biggest contention against biomass as a clean energy is the pollution that is created from burning the wood and other natural materials. Sometimes, they’re as bad as the pollution that comes from coal and other types of energy resources. There are a number of different compounds that come from burning biomass. Even though biomass energy is considered to be renewable, it is hard to claim it is a clean or efficient power energy. 2. Can Lead to Deforestation: Wood is a major source of biomass energy. To produce considerable amount of power, large amount of wood and other waste products have to be burned. The desire to produce energy on a large scale can lead to deforestationthat would destroy the homes of large number of plants and animals. • ## Question: What is a physical quantity that has both magnitude and direction? Posted in: Physics | Date: 11/03/2018 ### Answer: Vectors have magnitude and direction, scalars onlyhave magnitude. The fact that magnitude occurs forboth scalars and vectors can lead to some confusion. There are some quantities, like speed, which havevery special definitions for scientists. By definition, speed is the scalar magnitude of a velocity vector. • ## Question: Is biodiesel more efficient than gasoline? Posted in: Chemistry | Date: 11/03/2018 ### Answer: The Efficiency Of Biodiesel Fuel. The use of Biodiesel fuel for standard diesel engines, either alone or in combination with other fuels, has gathered much attention mostly because of its possible environmental and long-term economical benefits over fossil fuel. • ## Question: What is the magnitude of the earthquake? Posted in: Physics | Date: 11/03/2018 ### Answer: Magnitude calculations are based on a logarithmic scale, so a ten-fold drop in amplitude decreases the magnitude by 1. If an amplitude of 20 millimetres as measured on a seismicsignal corresponds to a magnitude 2 earthquake, then: ... 1000 times less (0.02 millimetres) corresponds to magnitude-1. • ## Question: What is a negative magnitude earthquake? Posted in: Physics | Date: 11/03/2018 ### Answer: Magnitude calculations are based on a logarithmic scale, so a ten-fold drop in amplitude decreases the magnitude by 1. If an amplitude of 20 millimetres as measured on a seismicsignal corresponds to a magnitude 2 earthquake, then: ... 1000 times less (0.02 millimetres) corresponds to magnitude-1. • ## Question: Can you have a negative magnitude? Posted in: Chemistry | Date: 11/03/2018 ### Answer: Negative numbers are always positive in the world of magnitude and absolute value. For example, the magnitude of 3.14 will always be 3.14 because the absolute value of a positive number is always itself. ... Only when you are dealing with the absolute value of simple numbers can you ignore it. • ## Question: Is it possible to add two vectors of unequal magnitude and get zero? Posted in: Physics | Date: 11/03/2018 ### Answer: Yes, two vectors of equal magnitude that are pointing in opposite directions willsum to zero. Two vectors of unequal magnitude can never sum to zero. If they point along the same line, since their magnitudes are different, the sum will not bezero. • ## Question: What is the parallel vector? Posted in: Physics | Date: 11/03/2018 ### Answer: Parallel vectors (parallel displacements) Twovectors u and v are parallel if and only if u = kv where k is a constant. ... If two vectors are parallelthen the corresponding directed line segments have a common direction. • ## Question: What makes a vector equal? Posted in: Physics | Date: 11/03/2018 ### Answer: For two vectors to be equal, they must have both the magnitude and the directionsequal. • ## Question: How are vectors collinear? Posted in: Physics | Date: 11/03/2018 ### Answer: If ab + bc = ac then the three points are collinear. The line segments can be translated to vectors ab, bc and ac where the magnitude of the vectors are equal to the length of the respective line segments mentioned. • ## Question: What is the sum of two or more vectors? Posted in: Physics | Date: 11/03/2018 ### Answer: The sum of two or more vectors is called the resultant. The resultant of two vectors can be found using either the parallelogram method or the triangle method . • ## Question: What is the dot product of two parallel vectors? Posted in: Physics | Date: 11/03/2018 ### Answer: if Two vectors are parallel then their dot product is 1. • ## Question: What is the difference between biomass and biofuels? Posted in: Chemistry | Date: 11/03/2018 ### Answer: Since biomass and biofuel both come from the same source, the natural organic products of the planet. The Difference between Biomass and Biofuel is simply that biomass is used to produce biofuel. Since the world has come to realize the benefits of this remarkable natural source many energy products have been developed. Biofuels come in many forms, there are biogases, liquid fuels and solid biomass. They all produce some sort of energy that is needed to operate the various machineries of today's society. They are especially prominent in Europe where they have been welcomed as a viable source of clean and efficient fuel. There have been many experiments conducted over the years concerning adapting biomass to use in the everyday life of a population. The fact that oil has risen in price and must be transported long distances has been a factor that has encouraged further development in the use of this organic matter. In addition, there has been increasing concern regarding depending on foreign nations for a product which is needed for a smooth operation of a country. The desire of scientists, as well as the population as a whole, is to have an energy source that is readily available and easy to use. The original use of biomass was for the production of bioethenal and biodiesel. The products used for production were mostly grains and seeds. Current fuels produced by method of fermentation are alcohols such as ethanol, propanol, and butanol. The most common biofuel is ethanol which is produced by fermentation and is mixed with gasoline for car engines as well as for other operations which need this type of gas. Green diesel is a very interesting product derived from biomass. It is made from renewable feedstock and is combined with regular diesel fuel. It is produced from oils which, in turn, are derived from plants, hence back to the biomass. In Europe, this is the preferred fuel for vehicles that use diesel fuel and is much less expensive. While it can be mixed with regular diesel, it is recommended that it only be 15% of the mixture. • ## Question: How do you find the resultant of two vectors? Posted in: Physics | Date: 11/03/2018 ### Answer: The resultant vector is the vector that 'results' from adding two or more vectors together. There are a two different ways to calculate the resultant vector. Methods for calculating a Resultant Vector • The head to tail method to calculate a resultant which involves lining up the head of the one vector with the tail of the other. • The parallelogram method to calculate resultant vector. This method involves properties of parallelograms but, in the end, boils down to a simple formula. • ## Question: What is synapes? Posted in: Biology | Date: 11/03/2018 ### Answer: In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target efferent cell. • ## Question: What are effecters and how they respond? Posted in: Biology | Date: 11/03/2018 ### Answer: In biochemistry, an effector molecule is usually a small molecule that selectively binds to a protein and regulates its biological activity. In this manner, effectormolecules act as ligands that can increase or decrease enzyme activity, gene expression, or cell signalling. • ## Question: What are neurolgia? Posted in: Biology | Date: 11/03/2018 ### Answer: Neuroglia, also called glial cell or glia, any of several types of cell that function primarily to support neurons. The term neuroglia means “nerve glue.” ... Neurons form a minority of the cells in the nervous system. • ## Question: What are sleep movements? Posted in: Biology | Date: 11/03/2018 ### Answer: It is the only movement disorder that occurs only during sleep, and it is sometimes called periodic leg (or limb) movements during sleep. ... PLMD is also considered a sleep disorder because the movements often disrupt sleep and lead to daytime sleepiness. PLMD may occur with other sleep disorders • ## Question: What role hormones play in kidney? Posted in: Biology | Date: 11/03/2018 ### Answer: The kidney is directed to excrete or retain sodium via the action of aldosterone,antidiuretic hormone (ADH, or vasopressin), atrial natriuretic peptide (ANP), and other hormones. Abnormal ranges of the fractional excretion of sodium can imply acute tubular necrosis or glomerular dysfunction. • ## Question: What are homeotherms? Posted in: Biology | Date: 11/03/2018 ### Answer: an organism that maintains its body temperature at a constant level, usually above that of the environment, by its metabolic activity. • ## Question: What are heat shock protiens? Posted in: Biology | Date: 11/03/2018 ### Answer: A protein induced in a living cell in response to a rise in temperature above the normal level. Several heat shock proteins function as intra-cellular chaperones for otherproteins. They play an important role in protein–protein interactions such as folding and assisting in the establishment of proper protein conformation (shape) and prevention of unwanted proteinaggregation. • ## Question: What are poikilotherms? Posted in: Biology | Date: 11/03/2018 ### Answer: An organism that cannot regulate its body temperature except by behavioural means such as basking or burrowing. • ## Question: How peritonial dialysis is done? Posted in: Biology | Date: 11/03/2018 ### Answer: During peritoneal dialysis, a cleansing fluid (dialysate) is circulated through a tube (catheter) inside part of your abdominal cavity (peritonealcavity). The dialysate absorbs waste products from blood vessels in your abdominal lining (peritoneum) and then is drawn back out of your body and discarded • ## Question: What is counter current multiplier? Posted in: Biology | Date: 11/03/2018 ### Answer: A countercurrent mechanism system is amechanism that expends energy to create a concentration gradient. ... For example, it can refer to the process that is underlying the process of urine concentration, that is, the production of hyperosmotic urine by the mammalian kidney. • ## Question: What is the basic procedure for cel animation ? Posted in: Animation | Date: 11/03/2018 ### Answer: Traditional animation (or classical animation, cel animation or hand-drawnanimation) is an animation technique where each frame is drawn by hand. Thetechnique was the dominant form of animation in cinema until the advent of computer animation. • ## Question: Differentiate between ureter and urethra? Posted in: Biology | Date: 11/03/2018 ### Answer: The ureters run from the kidneys to the bladder whilst theurethra runs from the bladder to exit the body: The renal papillae are the site where urine drains into one of the minor calyxes of the kidney. • ## Question: What are flame cells? Posted in: Biology | Date: 11/03/2018 ### Answer: A flame cell is a specialized excretory cell found in the simplest freshwater invertebrates, including flatworms (except the turbellarian order Acoela), rotifers and nemerteans; these are the simplest animals to have a dedicated excretory system. Flame cells function like a kidney, removing waste materials. • ## Question: What is themoregulation? Posted in: Biology | Date: 11/03/2018 ### Answer: Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. nthermoregulation, body heat is generated mostly in the deep organs, especially the liver, brain, and heart, and in contraction of skeletal muscles. Humans have been able to adapt to a great diversity of climates, including hot humid . • ## Question: What is meant by scan code? Posted in: Animation | Date: 11/03/2018 ### Answer: A scancode (or scan code) is the data that most computer keyboards send to a computer to report which keys have been pressed. A number, or sequence of numbers, is assigned to each key on the keyboard. • ## Question: What is the definition of the magnitude of a vector? Posted in: Physics | Date: 11/03/2018 ### Answer: The magnitude of a vector is the length of thevector. The magnitude of the vector is denoted as ∥ a ∥ . See the introduction tovectors for more about the magnitude of a vector. • ## Question: How do you calculate the magnitude of acceleration? Posted in: Physics | Date: 11/03/2018 ### Answer: Acceleration means the change of velocity of an object with respect to time. The ratio of change in velocity to the ratio of change in time in a given interval is the average acceleration. in that time interval. In simple words we can define acceleration, it means speeding up. The S. I. unit of acceleration is metre per second square and can be written as ms^{-2}. It is a vector Quantity. We know that magnitude is something where only distance covered is considered but not the displacement. Generally, the motions of objects are classified as motion in a straight line in a given time interval or the motion may be along a curve. The most common motion along a curve is the circular motion or rotation. The accelerations are broadly of two types : • Linear acceleration in case of linear motion • Angular acceleration in case of circular motion The magnitude of acceleration is something where we are considering only magnitude but not the direction. Of course, there will be change in direction in velocity in acceleration but we are not going to deal with that since we are considering only the circular motion, where direction is limited to two. In case of linear motions, the direction may be anything but in case of circular motion the directions are limited to two. The object may move in a clockwise direction or in a counter clock wise direction around the center of motion. The latter is considered positive as per convention. • ## Question: What is the dot product of two vectors? Posted in: Physics | Date: 11/03/2018 ### Answer: Algebraically, the dot product is the sum of the products of the corresponding entries of the two sequences of numbers. Geometrically, it is the product of the Euclidean magnitudes of the two vectors and the cosine of the angle between them. • ## Question: How do you know if two vectors are equal? Posted in: Physics | Date: 11/03/2018 ### Answer: You could compute the dot product of thetwo vectors, and if they are parallel (same direction) their dot product will be equal to the product of their individual norms. Then you can check norms and seeif they are equal (same magnitudes). Two vectors are equal if and only if all its components areequal. • ## Question: Can the magnitude of a vector be negative? Posted in: Physics | Date: 11/03/2018 ### Answer: Displacement is a vector and has direction while distance is a scalar) of my ball isnegative. However the magnitude of displacement is the absolute value of displacement which will always be positive. • ## Question: Can the sum of two unequal vectors be zero? Posted in: Physics | Date: 11/03/2018 ### Answer: Yes, two vectors of equal magnitude that are pointing in opposite directions will sum to zero. Two vectors of unequal magnitude can never sum to zero. If they point along the same line, since their magnitudes are different, the sum will not bezero. • ## Question: How can two vectors be equal? Posted in: Physics | Date: 11/03/2018 ### Answer: For two vectors to be equal, they must have both the magnitude and the directions equal. • ## Question: What is the largest country in Asia? Posted in: Geography | Date: 11/03/2018 ### Answer: Even after giving a share of its territory in Europe,Russia is the largest country in Asia. It is considered to be an Asian country. If it was a European nation, surely we would have seen Russia as a part of the EU. China is second with quite a many square miles behind. • ## Question: What are the rivers in Asia? Posted in: Geography | Date: 11/03/2018 ### Answer: Ganges The Ganges is the most sacred river to Hindus and is also a lifeline to millions of Indians who live along its course and depend on it for their daily needs. It is 1,560 miles (2,510 km) in length. Lena The Lena is the easternmost of the three great Siberian rivers that flow into the Arctic Ocean (the other two being the Ob River and the Yenisei River). It is the 11th longest river in the world at 2,734 miles (4,400 km). Indus The Indus River originates in Tibet and flows through India and Pakistan. It provides water resources for the economy of Pakistan - especially the Breadbasket of the southeast, which accounts for most of the nation's agricultural production. It is 1,800 miles (2,900 km) in length. Mekong The Mekong is the world's 10th-longest river and the 7th-longest in Asia. Its estimated length is 3,050 (4,909 km) and it provides inland transportation for the millions living along its banks, and tributaries Ob The Ob is a major river in western Siberia, Russia. The Ob is used mostly for irrigation, drinking water, hydroelectric energy, and fishing. It's 2,268 miles (3,650 km) in length. Yangtze China's Yangtze is the longest river in Asia, and the fourth longest in the world at 3,915 miles (6,301 km). The Yangtze drains one-fifth of the land area of the People's Republic of China and its river basin is home to one-third of China's population. Yellow The Yellow River is the second-longest river in China and the sixth longest in the world at 3,395 miles (5,464 km) in length. It's called "the cradle of Chinese civilization" as its basin – specifically, the Wei valley – was the birthplace of ancient Chinese civilizations and the most prosperous region in early Chinese history. • ## Question: What are the major landforms in Asia? Posted in: Geography | Date: 11/03/2018 ### Answer: The significant landform features of Asia include the world's tallest mountain, the world's lowest point, the world's deepest lake, the world's longest coastline and some of the most important rivers on the planet. To access the major landforms of Asia (by category) follow the links below. DESERTS LAKES MOUNTAINS RIVERS MIDDLE EAST Landforms • ## Question: What is slurry? Posted in: Physics | Date: 11/03/2018 ### Answer: A semi-liquid mixture, typically of fine particles of manure, cement, or coal and water. • ## Question: Why do you sweat in a dry heat? Posted in: Geography | Date: 11/03/2018 ### Answer: As the water evaporates, it transfers the body's heat to the air. ... On dry days, sweat evaporates quickly, which means it also carries away heat faster. On humid days, when the air is already saturated with water, sweat evaporates more slowly. This explains why it feels so much hotter in high humidity. • ## Question: What is the difference between dry heat and humidity? Posted in: Geography | Date: 11/03/2018 ### Answer: In order for you to learn the difference between humid heat and dry heat, it is important for you to understand the heat index. The heat index is a scale that is used to measure the moisture or humidity in the air. When there is more moisture in the air, the temperature feels hotter than it actually is in real life. The difference is that the relative humidity is different for the same temperature and our body has more problem to cool down by perspiration when the humidity is high. Say, you feel the same temperature at 40% relative humidity and at 90%. In the former case, natural body perspiration is enough to cool us because it evaporates fast since it is dry air. But if it is 90%, it won't work as well and you will feel more the heat. Think about it this way: If you are on the beach on a sunny day and you are wet from swimming. You will feel colder because the water will evaporate thus taking energy as heat. But if you are in the fog, it won't make a difference if you are wet or not because at 100% relative humidity, no further evaporation is possible. • ## Question: What are non-renewable sources of energy? Posted in: Physics | Date: 11/03/2018 ### Answer: Non-renewable energy comes from sources that will run out or will not be replenished in our lifetimes—or even in many, many lifetimes. Most non-renewable energy sources are fossil fuels: coal, petroleum, and natural gas. Carbon is the main element infossil fuels • ## Question: Why is the ionosphere important to humans? Posted in: Geography | Date: 11/03/2018 ### Answer: The ionosphere is the part of the atmosphere that is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth. The most important characteristic of use to humankind is the way it reflects and refracts radio waves. It also protects us from dangerous radiation • ## Question: Which layer of the atmosphere do we live in? Posted in: Geography | Date: 11/03/2018 ### Answer: That would be the troposphere, the lowest layer, where nearly all the weather takes place. It contains about 75% of the mass of the atmosphere • ## Question: Which layer of the atmosphere has weather? Posted in: Geography | Date: 11/03/2018 ### Answer: The troposphere is the first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer. 2) Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun. • ## Question: What layer of the atmosphere has satellites? Posted in: Geography | Date: 11/03/2018 ### Answer: Exosphere. This is the outermost layer of the atmosphere. It extends from the top of the thermosphere to 6,200 miles (10,000 km ) above the earth. In this layer, atoms and molecules escape into space and satellites orbit the earth. • ## Question: What are the 4 minor layers of the atmosphere? Posted in: Geography | Date: 11/03/2018 ### Answer: Four Minor Layers: Ozonosphere, Ionosphere, Exosphere, Magnetosphere • ## Question: Which is the coldest layer of the atmosphere? Posted in: Geography | Date: 11/03/2018 ### Answer: As the mesosphere extends upward above the stratosphere, temperatures decrease. The coldest parts of our atmosphere are located in this layer and can reach –90°C. In the forth layer from Earth's surface, the thermosphere, the air is thin, meaning that there are far fewer air molecules. • ## Question: What are the different layers of the atmosphere? Posted in: Geography | Date: 11/03/2018 ### Answer: From highest to lowest, the five main layers are: Exosphere: 700 to 10,000 km (440 to 6,200 miles) Thermosphere: 80 to 700 km (50 to 440 miles) Mesosphere: 50 to 80 km (31 to 50 miles) Stratosphere: 12 to 50 km (7 to 31 miles) Troposphere: 0 to 12 km (0 to 7 miles) • ## Question: What is the Earth's atmosphere made up of? Posted in: Geography | Date: 11/03/2018 ### Answer: Earth's atmosphere is 78% nitrogen, 21% oxygen, 0.9% argon, and 0.03% carbon dioxide with very small percentages of other elements. Our atmosphere also contains water vapor. In addition, Earth's atmosphere contains traces of dust particles, pollen, plant grains and other solid particles. • ## Question: What the sun is made of? Posted in: Geography | Date: 11/03/2018 ### Answer: The Sun is a huge, glowing sphere of hot gas. Most of this gas is hydrogen (about 70%) and helium (about 28%). Carbon, nitrogen and oxygen make up 1.5% and the other 0.5% is made up of small amounts of many other elements such as neon, iron, silicon, magnesium and sulfur. • ## Question: What are the different parts of the sun? Posted in: Geography | Date: 11/03/2018 ### Answer: There are three main parts to the Sun's interior: the core, the radiative zone, and the convective zone. The core is at the center. It the hottest region, where the nuclear fusion reactions that power the Sun occur. Moving outward, next comes the radiative (or radiation) zone. • ## Question: What are the three layers of the sun's atmosphere? Posted in: Geography | Date: 11/03/2018 ### Answer: The atmosphere of the sun is composed of several layers, mainly the photosphere, the chromosphere and the corona. It's in these outer layers that the sun's energy, which has bubbled up from the sun's interior layers, is detected as sunlight. The lowest layer of the sun's atmosphere is the photosphere. • ## Question: What is the meaning of plant pathology? Posted in: Biology | Date: 11/03/2018 ### Answer: Plant Pathology is defined as the study of the organisms and environmental conditions that cause disease in plants, the mechanisms by which this occurs, the interactions between these causal agents and the plant (effects on plant growth, yield and quality), and the methods of managing or controlling plant disease. • ## Question: What are the three layers of the sun's interior? Posted in: Geography | Date: 11/03/2018 ### Answer: The atmosphere of the sun is composed of several layers, mainly the photosphere, the chromosphere and the corona. It's in these outer layers that the sun's energy, which has bubbled up from the sun's interior layers, is detected as sunlight. The lowest layer of the sun's atmosphere is the photosphere. • ## Question: What are non-renewable sources of energy? Posted in: Physics | Date: 11/03/2018 ### Answer: Non-renewable energy comes from sources that will run out or will not be replenished in our lifetimes—or even in many, many lifetimes. Most non-renewable energy sources are fossil fuels: coal, petroleum, and natural gas. Carbon is the main element in fossil fuels. An example is carbon-based, organically-derived fuel. ... Earth minerals and metal ores, fossil fuels (coal, petroleum, natural gas) and groundwater in certain aquifers are all considered non-renewable resources • ## Question: What is the largest magnet in the world? Posted in: Physics | Date: 11/03/2018 ### Answer: The biggest (at least in size) magnet I know of is the superconducting solenoidal magnet of the CMS experiment on the Large Hadron Collider at CERN in Geneva, Switzerland • ## Question: What are the physical properties of a liquid? Posted in: Chemistry | Date: 11/03/2018 ### Answer: The most obvious physical properties of a liquid are its retention of volume and its conformation to the shape of its container. When a liquid substance is poured into a vessel, it takes the shape of the vessel, and, as long as the substance stays in the liquid state, it will remain inside the vessel. • ## Question: What are the eight physical properties of water? Posted in: Chemistry | Date: 11/03/2018 ### Answer: polarity. All of water's unique physical properties are caused by water's. Cohesion. water molecules stick to each other. ... Adhesion. water molecules stick to other surfaces. Surface Tension. ... Water has a high boiling point. ... Water's ability to dissolve other substances. ... ice is less dense than H2O. ... temperature moderartion. • ## Question: What is the strongest radiation? Posted in: Chemistry | Date: 11/03/2018 ### Answer: Alpha rays are the weakest and can be blocked by human skin and gamma rays are the strongest and only dense elements like lead can block them • ## Question: What are the four main types of radiation? Posted in: Chemistry | Date: 11/03/2018 ### Answer: The radiation one typically encounters is one of four types: alpha radiation, beta radiation, gamma radiation, x radiation. • ## Question: What is the magnetic effect of an electric current? Posted in: Physics | Date: 11/03/2018 ### Answer: Similar to other effects; electric current also produces magnetic effect. The magnetic effect of electric current is known as electromagnetic effect. It is observed that when a compass is brought near a current carrying conductor the needle of compass gets deflected because of flow of electricity. • ## Question: Are alpha particles positive or negative? Posted in: Chemistry | Date: 11/03/2018 ### Answer: The alpha particle is a helium nucleus; it consists of two protons and two neutrons. It contains no electrons to balance the two positively charged protons. Alpha particles are therefore positively charged particles moving at high speeds • ## Question: What is an example of a magnetic field? Posted in: Physics | Date: 11/03/2018 ### Answer: An example of a magnetic field is the Earth's magnetic field. • ## Question: If A.M. and G.M. of the roots of a quadratic equation are 6 and 9, respectively,... Posted in: Mathematics | Date: 12/03/2018 ### Answer: Let the root of the quadratic equation be a and b. According to the given condition,ab−− A.M.=a+b/2 a+b=16 & G.M.=√ab=5 ab=25 The quadratic equation is given by, x2– x (Sum of roots) + (Product of roots) = 0 x2 – x (a + b) + (ab) = 0 x2 – 16x + 25 = 0 [Using (1) and (2)] Thus, the required quadratic equation is x2 – 16x + 25 = 0 • ## Question: What are the three different types of hormones? Posted in: Biology | Date: 12/03/2018 ### Answer: Types of hormones Steroid hormones – these are made from cholesterol. ... Eicosanoids: these are lipid hormones – hormones made from lipids, kinds of fats. ... Amino acid derived. ... Peptides, polypeptides and proteins – small peptide hormones include TRH and vasopressin. • ## Question: Which hormones are found in females? Posted in: Biology | Date: 12/03/2018 ### Answer: The hormones controlling the female reproductive system includegonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH) and leutenizing hormone (LH), all of which are produced in the brain; oestrogen and progesterone produced by the ovaries and the corpus luteum; and human chorionic gonadotropin (HCG) • ## Question: What is bond dissociation energy Posted in: Chemistry | Date: 12/03/2018 ### Answer: Bond-dissociation energy (BDE ) is one measure of the strength of a chemical bond. It can be defined as the standard enthalpy change when a bond is cleaved by homolysis, with reactants and products of the homolysis reaction at 0 K (absolute zero). • ## Question: What are population pyramids? How do they help in understanding about the popula... Posted in: Geography | Date: 12/03/2018 ### Answer: The Population Pyramid in which birth and death rate both are high is broad at the base and narrow at the top. This is because although many children are born ,a large of them die in their infanty and relatively few become adult and there are very few old people. In countires where death rate (especially among the very young ) are decreasing, the pyramid in younger age groups ,because more infant survive to adulthood. • ## Question: Explain the structure of traditional seed drill. Posted in: Biology | Date: 12/03/2018 ### Answer: A seed drill is a device that sows the seeds for crops by metering out the individual seeds, positioning them in the soil, and covering them to a certain average depth. The seed drill sows the seeds at equal distances and proper depth, ensuring that the seeds get covered with soil and are saved from being eaten by birds. For accurate and precise seeding, the crop should be drilled using a multi crop planter with a precise seed-metering system (e.g., inclined plate, cupping system, or vertical plates) With these precise seed-metering planters, rice can be established with a lower seed rate and more precise plant-to-plant spacing can be maintained. Normal fluted roller-type seed-cum-fertilizer drills are less suitable for drill seeding of rice as the seeds fall continuously. This makes it difficult to maintain the seed rate and plant-to-plant spacing as accurate and precise as that in inclined-/cupping-/vertical-plate seed-metering systems . It is difficult to drill rice at a low seed rate of 20–25 kg ha− 1 with a fluted roller seed drill because it breaks the seeds. If farmers do not have inclined-plate planters, they can seed at a lower rate with a normal drill by mixing with sand to increase the seed volume and opening of the fluted roller so that breakage of rice can be avoided It tills the soil shallow (4–5 cm), sows seed in rows, and covers it with soil at the same time in a single pass. • ## Question: What are the advantages of manure? Posted in: Biology | Date: 12/03/2018 ### Answer: Advantages of using manure in farming and garden are as follows: Manure in the form of animal dung is being used as fertilizer in farming for many centuries, it improves the soil structure. It helps hold more water and nutrients in the soil and makes the soil more fertile. Application of manure to soil also improves microbial activity which enhances the mineral supply of the soil thereby improving plant nutrition. It improves the nitrogen content and other nutrients in the soil promoting plant growth. Manure is an organic product and environment friendly, does not cause harm to the environment. It helps to concentrates nutrients in the soil. It is easier to transport. Compost manure helps kill parasites. Manure being organic can be used in organic systems, Manure can be used on land and the food grown her is fit for direct human consumption. It kills weed seeds. Odor from manure is subsided when it is spread. In the case of aquatic plants organic fertilizers have other important plant nutrients other than nitrogen and phosphorus which is beneficial for the growth of planktons. Organic maure fertilizers which are coated with bacteria can be used to directly as food by cultured species. Use of organic moisture can help retain the moisture in the soil and prevents lose of natural nutrients and minerals from the soil. Methane gas is the by-product of manure; methane gas can be used as biogas for cooking and heating purposes. • ## Question: Which hormone controls blood sugar levels? Posted in: Biology | Date: 12/03/2018 ### Answer: Insulin Insulin and glucagon are hormones secreted by islet cells within the pancreas. They are both secreted in response to blood sugar levels, but in opposite fashion! Insulin is normally secreted by the beta cells (a type of islet cell) of the pancreas. • ## Question: What is the effect of soil compaction? Posted in: Geography | Date: 12/03/2018 ### Answer: In geotechnical engineering, soil compaction is the process in which a stress applied to a soil causes densification as air is displaced from the pores between the soil grains. ... Affected soils become less able to absorb rainfall, thus increasing runoff and erosion. Effects of compaction on pore space. Soil compaction occurs when soil particles are pressed together, reducing pore space between them . Heavily compacted soils contain few large pores and have a reduced rate of both water infiltration and drainage from the compacted layer. • ## Question: What does soil pollution affect? Posted in: Geography | Date: 12/03/2018 ### Answer: Soil pollution occurs when the presence of toxic chemicals, pollutants or contaminants in the soil is in high enough concentrations to be of risk to plants, wildlife, humans and of course, the soil itself. Arable land is turning to desert and becoming non-arable at ever-increasing rates, due largely in part to global warming and agricultural fertilizers and pesticides, lessening the hope that we can feed our booming population Soil pollution can have a number of harmful effects on ecosystems and human, plants and animal health. The harmful effects of soil pollution may come from direct contact with polluted soil or from contact with other resources, such as water or food which has been grown on or come in direct contact with the polluted soil. • ## Question: When the dot product of two vectors is 0? Posted in: Physics | Date: 12/03/2018 ### Answer: If A and B are perpendicular (at 90 degrees to each other), the result of the dot product will be zero, because cos(Θ) will be zero. If the angle between A and B are less than 90 degrees, the dot product will be positive (greater than zero), as cos(Θ) will be positive, and the vector lengths are always positive values. • ## Question: What is a vector file format? Posted in: Physics | Date: 12/03/2018 ### Answer: Because it is vector it can easily be resized to any size it needs to be. An EPS file can be reopened and edited. Best use = master logo files and graphics and print designs. AI. An AI file is a proprietary, vector file type created by Adobe that can only be created or edited with Adobe Illustrator. • ## Question: What are the pros and cons of hydroelectric power? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Advantages of Hydroelectric Energy 1. Renewable Hydroelectric energy is renewable. This means that we cannot use up. However, there’s only a limited number of suitable reservoirs where hydroelectric power plants can be built and even less places where such projects are profitable. 2. Green Generating electricity with hydro energy is not polluting itself. The only pollution occurs during the construction of these massive power plants. 3. Reliable Hydroelectricity is very reliable energy. There are very little fluctuations in terms of the electric power that is being by the plants, unless a different output is desired. Countries that have large resources of hydropower use hydroelectricity as a base load energy source. As long as there is water in the magazines electricity can be generated. 4. Flexible As previously mentioned, adjusting water flow and output of electricity is easy. At times where power consumption is low, water flow is reduced and the magazine levels are being conserved for times when the power consumption is high. 5. Safe Compared to among others fossil fuels and nuclear energy, hydroelectricity is much safer. There is no fuel involved (other than water that is). Cons of Hydroelectric Power Environmental damage. Interruptions of natural water flow can have a great impact the river ecosystem and the environment. ... High upfront capital costs. ... Might cause conflicts. ... May lead to droughts. ... Risk of floods in lower elevations. ... Carbon dioxide and methane emission. • ## Question: What is the formula for the magnitude of a vector? Posted in: Physics | Date: 12/03/2018 ### Answer: The magnitude of a vector P Q → is the distance between the initial point and the end point . In symbols the magnitude of P Q → is written as. P Q → . If the coordinates of the initial point and the end point of a vector is given, the Distance Formula can be used to find its magnitude. • ## Question: How are vectors drawn? Posted in: Physics | Date: 12/03/2018 ### Answer: The magnitude and direction of the sum of two or more vectors can also be determined by use of an accurately drawn scaled vector diagram. Using a scaled diagram, the head-to-tail method is employed to determine the vector sum or resultant. • ## Question: What is the resultant of two vectors? Posted in: Physics | Date: 12/03/2018 ### Answer: The resultant is the vector sum of two or more vectors. It is the result of adding two or more vectors together. If displacement vectors A, B, and C are added together, the result will be vector R. vector R can be determined by the use of an accurately drawn, scaled, vector addition diagram. • ## Question: What are the disadvantages of using biodiesel? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Disadvantages of biodiesel: At present, biodiesel fuel is more expensive than petroleum diesel fuel. Biofuels are a solvent and therefore can harm rubber hoses in some engines. As a solvent, biodiesel cleans dirt from engines. This dirt can then get collected in fuel filters, clogging them. As a result, filters have to be changed after the first several hours of biodiesel use. Biodiesel fuel distribution infrastructure needs improvement to make biodiesel more widely available. In cold weather, pure biodiesel can thicken or gel, making it hard to pump. • ## Question: What do you call the sum of two vectors? Posted in: Physics | Date: 12/03/2018 ### Answer: Two vectors are equal if they have the same magnitude and direction. They are parallel if they have the same or opposite direction. We can combine vectors by adding them, the sum of two vectors is called the resultant. • ## Question: What is the condition for two vectors to be perpendicular to each other? Posted in: Physics | Date: 12/03/2018 ### Answer: Two vectors are perpendicular if the angle between them is π2π2, i.e., if the dot product is 00. This follows from the fact that for two vectors v⃗ ,w⃗ v→,w→, we have v⃗ ⋅w⃗ =|v⃗ ||w⃗ |cos(θ)v→⋅w→=|v→||w→|cos⁡(θ), where θθ is the angle between v⃗ v→ and w⃗ w→. • ## Question: What is the scalar product of two vectors? Posted in: Physics | Date: 12/03/2018 ### Answer: A vector quantity is defined as a physical quantity which has both magnitude and direction. ... A scalar quantity is a quantity which has magnitude only but no direction. For example, distance, speed etc. It is impossible to add the two together because of their different dimensions • ## Question: Can you add a vector and a scalar? Posted in: Physics | Date: 12/03/2018 ### Answer: A vector quantity is defined as a physical quantity which has both magnitude and direction. ... A scalar quantity is a quantity which has magnitude only but no direction. For example, distance, speed etc. It is impossible to add the two together because of their different dimensions • ## Question: What is the polygon law of vector addition? Posted in: Physics | Date: 12/03/2018 ### Answer: Polygon law of vector addition states that if a number of vector are represented completely by the side of a polygon taken in order their resultant is fully represented by the closing side of the polygon taken in opposite order. • ## Question: Is biofuel energy renewable or nonrenewable? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Biofuel, a renewable energy source derived from organic matter such as wood, crop waste, or garbage, • ## Question: What are the advantages and disadvantages of using biodiesel? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Advantages of biodiesel: Biodiesel fuel is a renewable energy source, unlike petroleum-based diesel. Biodiesel is less polluting than petroleum diesel. The lack of sulfur in 100% biodiesel extends the life of catalytic converters. Biodiesel can be blended with other energy resources and oil. Biodiesel fuel can be used in existing oil heating systems and diesel engines without any alterations to those systems or engines. Biodiesel can be distributed through existing diesel fuel pumps, which is another advantage over other alternative fuels. Sulfur, which acts as a lubricating agent, must be removed from conventional petroleum-based diesel fuel. The lubricating property of biodiesel fuel can lengthen the lifetime of engines. Disadvantages of biodiesel: At present, biodiesel fuel is more expensive than petroleum diesel fuel. Biofuels are a solvent and therefore can harm rubber hoses in some engines. As a solvent, biodiesel cleans dirt from engines. This dirt can then get collected in fuel filters, clogging them. As a result, filters have to be changed after the first several hours of biodiesel use. Biodiesel fuel distribution infrastructure needs improvement to make biodiesel more widely available. In cold weather, pure biodiesel can thicken or gel, making it hard to pump. • ## Question: What are the disadvantages of using nuclear power? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Disadvantages of Nuclear Energy In spite of its many benefits, nuclear energy often falls under fire because of the many disadvantages it brings. That’s not to say that nuclear energy is not useful; we’re just pointing out the risks that are also involved. 1. Raw Material The uranium used in the process of fission is a naturally unstable element. In other words, it means that the people working in mining, transporting, and storing of uranium must take special precautions. The same goes for the storing of any waste product resulting from the fission process; extra safety measures are meant to prevent uranium from emitting harmful levels of radiation. 2. Fuel Availability Fossil fuels can be found and mined in many countries. However, the same cannot be said about uranium, which is a very scarce resource. Only a few countries have uranium ores, which means that a tiresome process of getting the approval of several international authorities is required before anyone can build a nuclear power plant. 3. High Cost Even if you do get permission to build a plant that uses nuclear energy, you stumble upon another disadvantage: the massive investment required to set up a functional nuclear power station. Developing countries can rarely afford to use nuclear energy because it’s such a costly source of alternative energy. Meanwhile, nuclear power plants usually take 5 to 10 years to build; there is a mountain of legal formalities to be approved beforehand and the people living nearby the potential site usually oppose the project. . Nuclear Waste After the uranium splits to generate heat, the resulting byproducts are radioactive, which means they need to be removed in a safe way. Even though power plants have undergone recycling efforts of this waste product in recent years, storing the byproduct can lead to contamination through various containment failures. 5. Water Pollutant The chambers where nuclear fission takes place need to be cooled down by water. Then, this water is turned into steam, which powers the massive turbines. After the water cools down and changes back into liquid form, the plant pumps it outside into nearby wetlands. While measures ensure radiation does not leak into the environment, other heavy metals and pollutants often escape the chambers. The hot water also gives off immense heat that damages to ecosystems nearby the reactor. • ## Question: What is the difference between biogas and biofuels? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Put simply, biofuel is energy made from living matter, usually plants. Bioethanol, biodiesel, and biogas are types of biofuels. ... Bioethanol (aka ethanol) is the most well know biofuel and is an alcohol produced from corn, sorghum, potatoes, wheat, sugar cane, even cornstalks and vegetable waste. • ## Question: What is biofuel made of? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Biofuels are made mostly from plants that have just been harvested. There are three main types of biofuel. Ethanol, biodiesel, and biojet fuel. • ## Question: How is bioethanol is produced? Posted in: Chemistry | Date: 12/03/2018 ### Answer: The principle fuel used as a petroleum substitute is bioethanol. Bioethanol is mainly produced by the sugar fermentation process, although it can also be produced by the chemical process of reacting ethylene with steam. The main source of sugar required to produce ethanol comes from fuel or energy crops. • ## Question: What is bioethanol and what is it used for? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Bioethanol is ethanol derived exclusively from the fermentation of plant starches and used to fuel combustion engines with fewer emissions. It is currently used in the fuel industry as an additive for petrol. • ## Question: What is the difference between biodiesel and biofuels? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Biodiesel is made from vegetable oils (palm oil, soybean oil) and animal fat. Biofuels are made from components other than petroleum derived products such as human and animal wastes, landfill gases, agricultural, and industrial wastes, etc. • The resources for biofuel production are abundant in everywhere compared to the biodiesel production. However, compared to the fossil fuel production, resources are more available for both bio fuel and biodiesel production. • Biodiesel is non-toxic and biodegradable, but some of the biofuels contain toxic gases. • There are various impacts of the petroleum based industries such as social, economic, environmental, cultural, and medical. However, the impact of the biodies els and biofuel is comparatively less. • ## Question: What are the different types of biofuels? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Bioalcohol Ethanol Propanol ButanolStarches from wheat, corn, sugar cane, molasses, potatoes, other fruitsBiodieselOils and fats including animal fats, vegetable oils, nut oils, hemp, and algaeGreen DieselMade from hydrocracking oil and fat feedstock • ## Question: What is passive and active flight? Posted in: Biology | Date: 12/03/2018 ### Answer: Wings help create the aerodynamic forces (lift and thrust) necessary for flight. ... Active flight consists in moving through the air by flapping the wings; passive flight involves gliding and soaring • ## Question: What are the causes of cramps? Posted in: Biology | Date: 12/03/2018 ### Answer: Overuse of a muscle, dehydration, muscle strain or simply holding a position for a prolonged period can cause a muscle cramp. In many cases, however, the cause isn't known. Although most muscle cramps are harmless, some may be related to an underlying medical condition, such as: Inadequate blood supply. • ## Question: What is rigor mortis? Posted in: Biology | Date: 12/03/2018 ### Answer: Rigor Mortis: ]stiffening of the joints and muscles of a body a few hours after death, usually lasting from one to four days. • ## Question: What is hematoma formation? Posted in: Biology | Date: 12/03/2018 ### Answer: A hematoma is an abnormal collection of blood outside of a blood vessel. It occurs because the wall of a blood vessel wall, artery, vein, or capillary, has been damaged and blood has leaked into tissues where it does not belong. ... The blood vessels in the body are under constant repair. • ## Question: What is ecdysis or molting? Posted in: Biology | Date: 12/03/2018 ### Answer: Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remnants of the old, empty exoskeleton are called exuviae • ## Question: What are pyrogens? Posted in: Biology | Date: 12/03/2018 ### Answer: a substance, typically produced by a bacterium, which produces fever when introduced or released into the blood. • ## Question: What does the dot product of two vectors give you? Posted in: Physics | Date: 12/03/2018 ### Answer: the dot product of two vectors will be equal to the cosine of the angle between the vectors, times the lengths of each of the vectors. Angular Domain of Dot Product: ... If A and B are perpendicular (at 90 degrees to each other), the result of the dot product will be zero, because cos(Θ) will be zero. • ## Question: What is the magnitude of the centripetal acceleration? Posted in: Physics | Date: 12/03/2018 ### Answer: The direction of the centripital acceleration is always inwards along the radius vector of the circular motion. The magnitude of the centripetal acceleration is related to the tangential speed and angular velocity as follows: ac = = r. • ## Question: How do you calculate the magnitude of a vector? Posted in: Physics | Date: 12/03/2018 ### Answer: Draw a vector triangle. When you draw the horizontal and vertical components, you end up with a right triangle. The magnitude of the vector is equal to the hypotenuse of the triangle so you can use the Pythagorean theorem to calculate it. Rearrange the Pythagorean theorem to calculate the magnitude • ## Question: What is meant by magnitude of a vector? Posted in: Physics | Date: 12/03/2018 ### Answer: The magnitude of a vector is the length of the vector. The magnitude of the vector is denoted as ∥ a ∥ . See the introduction to vectors for more about the magnitude of a vector. • ## Question: What are the components of a vector? Posted in: Physics | Date: 12/03/2018 ### Answer: In physics, when you break a vector into its parts, those parts are called its components. For example, in the vector (4, 1), the x-axis (horizontal) component is 4, and the y-axis (vertical) component is 1. • ## Question: How would you define the zero vector? Posted in: Physics | Date: 12/03/2018 ### Answer: A zero vector has no magnitude , a Zero vector has no direction. Still it is called a vector because we get a zero vector after addition of two vectors. A zero vector or null vector therefore has only mathematical requirement. If sum of 2 vectors is zero vector, they must be anti parallel to each other. • ## Question: What is zero vector in physics? Posted in: Physics | Date: 12/03/2018 ### Answer: A zero vector has no magnitude , a Zero vector has no direction. Still it is called a vector because we get a zero vector after addition of two vectors. A zero vector or null vector therefore has only mathematical requirement. If sum of 2 vectors is zero vector, they must be anti parallel to each other. • ## Question: Can you have a vector of zero? Posted in: Physics | Date: 12/03/2018 ### Answer: yes A zero vector has no magnitude , a Zero vector has no direction. Still it is called a vector because we get a zero vector after addition of two vectors. A zero vector or null vector therefore has only mathematical requirement. If sum of 2 vectors is zero vector, they must be anti parallel to each other. • ## Question: What is the meaning of collinear vector? Posted in: Physics | Date: 12/03/2018 ### Answer: Two vectors are collinear, if they lie on the same line or parallel lines. • ## Question: Can the magnitude of a vector be zero? Posted in: Physics | Date: 12/03/2018 ### Answer: No, a vector cannot have zero magnitude if one of its components is not zero. ... It can be seen from this equation that if any of or is non-zero, the magnitude of vector will also be non-zero. • ## Question: What is the second biggest country in Asia? Posted in: Geography | Date: 12/03/2018 ### Answer: China is second largest country in Asia. • ## Question: What are the landforms in India? Posted in: Geography | Date: 12/03/2018 ### Answer: Himalayas. The Himalaya Mountains serve as the northern boundary of India; some of the mountains and many of the surrounding foothills are within the country. ... Ganges River. The Ganges River runs 1,560 miles, beginning in the Himalayas and flowing into the Bay of Bengal. ... Thar Desert. ... Andaman Islands. • ## Question: Which layer of the atmosphere do meteors burn up? Posted in: Geography | Date: 12/03/2018 ### Answer: mesosphere—the layer in which most meteors burn up after entering Earth's atmosphere and before reaching Earth's surface. • ## Question: Which layer of the atmosphere contains the ozone? Posted in: Geography | Date: 12/03/2018 ### Answer: The Ozone layer is actually located in the stratosphere in a region that is 10 to 50 km above the Earth. • ## Question: Which layer of the Earth is the coolest? Posted in: Geography | Date: 12/03/2018 ### Answer: The crust or lithosphere is the coolest layer of earth. • ## Question: What does the Earth's atmosphere do? Posted in: Geography | Date: 12/03/2018 ### Answer: The atmosphere also protects living things on Earth from the sun's harmful ultraviolet radiation. A thin layer of gas called ozone high up in the atmosphere filters out these dangerous rays. The atmosphere also helps to sustain life of Earth. • ## Question: What is in the Earth's atmosphere? Posted in: Geography | Date: 12/03/2018 ### Answer: The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity. ... By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. • ## Question: What are the three parts of the earth's outer structure? Posted in: Geography | Date: 12/03/2018 ### Answer: The Earth's structure consists of three parts, the crust, mantle and core. The crust is on the outside, while the mantle is in the middle and the core is the innermost section. The core is divided into two parts, the inner core and the outer core. • ## Question: What is the difference between CADD and CAD? Posted in: Fashion Study | Date: 12/03/2018 ### Answer: Acronym for computer-aided design and drafting. CADD systems are CAD systems with additional drafting features. For example, CADD systems enable an engineer or architect to insert size annotations and other notes into a design. • ## Question: What is the structure and composition of the earth? Posted in: Geography | Date: 12/03/2018 ### Answer: Structure The Earth consists of four concentric layers: inner core, outer core, mantle and crust. The crust is made up of tectonic plates, which are in constant motion. Earthquakes and volcanoes are most likely to occur at plate boundaries. Composition: Chemical composition. Earth's mass is approximately5.97×1024 kg (5,970 Yg). It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. • ## Question: What is the meaning of physiological process? Posted in: Biology | Date: 12/03/2018 ### Answer: The branch of biology dealing with the functions and activities of living organisms and their parts, including all physical and chemical processes. 2. the organic processes or functions in an organism or in any of its parts. • ## Question: What is the pathology of plants? Posted in: Biology | Date: 12/03/2018 ### Answer: Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors • ## Question: What is a non-magnetic material? Posted in: Physics | Date: 12/03/2018 ### Answer: Nonmagnetic Materials. paramagnetic, diamagnetic, and weakly ferromagnetic materials with magnetic permeability μ≦ 1.5. Nonmagnetic materials include most metals and alloys, polymers, wood, and glass. • ## Question: What will attract a magnet? Posted in: Physics | Date: 12/03/2018 ### Answer: Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include iron, nickel, cobalt, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. • ## Question: Why are solenoids useful? Posted in: Physics | Date: 12/03/2018 ### Answer: A solenoid is just a coil of wire, but when you run a current through it, you create an electromagnet. ... Electromagnets are particularly useful because, unlike regular magnets, they can be switched on and off, and strengthened by increasing the current flowing through them. • ## Question: What is the value of k in electric field? Posted in: Physics | Date: 12/03/2018 ### Answer: The magnitude of the electric field (E) produced by a point charge with a charge of magnitude Q, at a point a distance r away from the point charge, is given by the equation E = kQ/r2, where k is a constant with a value of 8.99 x 109 N m2/C2. • ## Question: What are the symptoms of spleen problems? Posted in: Biology | Date: 12/03/2018 ### Answer: Symptoms are: No symptoms in some cases. Pain or fullness in the left upper abdomen that may spread to the left shoulder. Feeling full without eating or after eating only a small amount from the enlarged spleen pressing on your stomach. Anemia. Fatigue. Frequent infections. Easy bleeding. • ## Question: What is the most magnetic material in nature? Posted in: Physics | Date: 12/03/2018 ### Answer: A more powerful magnetic material may have emerged to topple previous record-holder iron cobalt, until now the most magnetic material on Earth. • ## Question: Which devices use electromagnets? Posted in: Physics | Date: 12/03/2018 ### Answer: Electromagnetic devices are devices that contain electromagnets. Examples of electromagnetic devices include doorbells and any devices that have electric motors, such as electric fans. The electromagnet in a doorbell attracts the clapper, which hits the bell and makes it ring. • ## Question: What is Mri? Posted in: Biology | Date: 12/03/2018 ### Answer: Magnetic resonance imaging (MRI) is a safe and painless test that uses a magnetic field and radio waves to produce detailed pictures of the body's organs and structures. An MRI differs from a CAT scan (also called a CT scan or a computed axial tomography scan) because it doesn't use radiation. • ## Question: What is Alzheimer's Disease? Posted in: Biology | Date: 12/03/2018 ### Answer: Alzheimer's is the most common form of dementia, a general term for memory loss and other cognitive abilities serious enough to interfere with daily life. Alzheimer's disease accounts for 60 to 80 percent of dementia cases. Alzheimer's is not a normal part of aging. The greatest known risk factor is increasing age, and the majority of people with Alzheimer's are 65 and older. But Alzheimer's is not just a disease of old age. Alzheimer's is a progressive disease, where dementia symptoms gradually worsen over a number of years. In its early stages, memory loss is mild, but with late-stage Alzheimer's, individuals lose the ability to carry on a conversation and respond to their environment. Alzheimer's is the sixth leading cause of death in the United States. Those with Alzheimer's live an average of eight years after their symptoms become noticeable to others, but survival can range from four to 20 years, depending on age and other health conditions. • ## Question: What Is Bmi? Posted in: Biology | Date: 12/03/2018 ### Answer: Body mass index (BMI) is a measure of body fat based on your weight in relation to your height, and applies to most adult men and women aged 20 and over. For children aged 2 and over, BMI percentile is the best assessment of body fat • ## Question: What Is Myoelectric Control? Posted in: Biology | Date: 12/03/2018 ### Answer: Myoelectric control is an advanced technique concerned with the detection, processing, classification, and application of myoelectric signals to control human-assisting robots or rehabilitation devices. • ## Question: Describe the Sling Hygrometer? Posted in: Fashion Designing | Date: 12/03/2018 ### Answer: Sling Psychrometer. Relative humidity can be measured by an instrument called a hygrometer. The simplest hygrometer - a sling psychrometer - consists of two thermometers mounted together with a handle attached on a chain. ... The other has a cloth wick over its bulb and is called a wet-bulb thermometer • ## Question: How muscle fatige is produce? Posted in: Biology | Date: 12/03/2018 ### Answer: If muscle weakness is the result of pain, the person may be able to make muscles work, but it will hurt. Fatigue is a feeling of tiredness or exhaustion or a need to rest because of lack of energy or strength. Fatigue may result from overwork, poor sleep, worry, boredom, or lack of exercise. • ## Question: What is jet propultion? Posted in: Biology | Date: 12/03/2018 ### Answer: jet propulsion is propulsion by the backward ejection of a high-speed jet of gas or liquid. • ## Question: What are the 12 principles of AA? Posted in: Animation | Date: 12/03/2018 ### Answer: The AA Principles and Virtues Honesty Step 1. We admitted that we were powerless over alcohol - that our lives had become unmanageable. Hope Step 2. Came to believe that a power greater than ourselves could restore us to sanity. Faith Step 3. Made a decision to turn our will and our lives over to the care of God as we understood him. Courage Step 4. Made a searching and fearless moral inventory of ourselves. Integrity Step 5. Admitted to God, to ourselves, and to another human being the exact nature of our wrongs. Willingness Step 6. Were entirely ready to have God remove all these defects of character. Humility Step 7. Humbly asked Him to remove our shortcomings. Brotherly Love Step 8. Made a list of all persons we had harmed, and became willing to make amends to them all. Discipline Step 9. Made direct amends to such people wherever possible, except when to do so would injure them or others. Perseverance Step 10. Continued to take personal inventory and when we were wrong promptly admitted it. Spirituality Step 11. Sought through prayer and meditation to improve our conscious contact with God as we understood Him, praying only for knowledge of His will for us and the power to carry that out. Service Step 12. Having had a spiritual awakening as the result of these steps, we tried to carry this message to others, especially alcoholics and to practice these principles in all our affairs. • ## Question: How do I define Epilepsy? Posted in: Biology | Date: 12/03/2018 ### Answer: Epilepsy is a condition in which a person has recurrent seizures. A seizure is defined as an abnormal, disorderly discharging of the brain's nerve cells, resulting in a temporary disturbance of motor, sensory, or mental function. • ## Question: What are the advantages and disadvantages of biodiesel? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Advantages of biodiesel It is Renewable – Since it is produced from organic materials – plants and animals – instead of from fossil fuels, biodiesel is much more renewable than its petroleum based counterparts. This means that it could potentially become a longer term replacement for fossil fuels if a viable alternative isn’t found². Its Manufacture is an Effective Recycling Method – Not only are biofuels produced from renewable, organic materials, but they can also be made from a huge range of these materials. They can be manufactured using anything from crop waste to feedlot manure, and are even an effective way of recycling used restaurant and cafe oils³. Economic Stimulation – Biofuel production can provide hundreds or even thousands of jobs in rural or remote areas. Since biofuels are produced locally, it is the local community who benefits, as opposed to fossil fuels which are usually produced offshore or in foreign countries by multinational corporations³. They Burn Cleanly – One of the major characterising factors which separate biodiesels from fossil fuels is the way in which they burn. They produce less carbon emissions than traditional fuels, which makes them cleaner and more environmentally friendly. They also produce no sulfur (as long as a 100% biodiesel is used), which improves air quality and actually increases the lifespan of diesel engines³. Disadvantages of biodiesel Biofuel Crops Compete With Food Crops – Since biofuels are produced from organic products, often corn or soybeans, they can compete with food production. This can lead to increased food prices, and even food shortages in poorer areas of the world. To fully harness the potential of biofuels, we need to be able to grow crops for food, and use the waste products for biofuel production⁴. Deforestation – One of the best biofuel sources in the world is palm oil. Yes, the nasty, environmentally destructive, palm oil. When the demand for biofuels began to increase at the end of the 90’s, people began to realise that palm oil was a great material to use to produce biofuels. However, they didn’t consider the environmental issues and drawbacks of producing palm oil in Indonesia and shipping it to Europe. Not only were forest cleared and burnt to make way for palm oil plantations, but a huge amount of fossil fuels was burnt in doing so – defeating the entire purpose of using biodiesels⁴. They Can’t Be Used in Cold Areas – This is one of the major drawbacks of biofuel use. If it gets too cold, then the fuel will begin to solidify inside the fuel tank and engine, meaning you won’t be able to drive anywhere until it warms up. The temperature of congelation will depend on the product that the biodiesel is made from, but can actually be relatively high. However, it can still be used in winter if you mix it with some sort of winterised diesel, which will help it remain a liquid¹. Increased Nitrogen Oxide Emissions – While biodiesels are cleaner than fossil fuels on average, they do tend to produce slightly more nitrogen oxide (about 10% more). This causes increased pollution around big cities and fuel use centers, and contributes to the formation of smog and acid rain • ## Question: What is an example of a vector? Posted in: Physics | Date: 12/03/2018 ### Answer: A vector is a quantity or phenomenon that has two independent properties: magnitude and direction. The term also denotes the mathematical or geometrical representation of such a quantity. Examples of vectors in nature are velocity, momentum, force, electromagnetic fields, and weight. • ## Question: Can you drink ethanol alcohol? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Vodka is ethanol. Ethanol diluted with water. Ethanol is ~96% ethanol, 4% water. Vodka is mostly 40% alcohol, 60% water. Ethanol is a poison, just not that strong or that fast. I wouldn't recommend consuming it at 75% ABV or higher. • ## Question: Do opposite vectors have a negative magnitude? Posted in: Physics | Date: 12/03/2018 ### Answer: Two vectors are equal if they have the same magnitude and the same direction. Just like scalars which can have positive or negative values, vectors can also be positive or negative. A negative vector is a vector which points in the direction opposite to the reference positive direction but magnitude will always be positive. • ## Question: What are the pros and cons of wind power? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Pros of Wind Power Wind energy is a green energy source and does not cause pollution. The potential of wind power is enormous – 20 times more than what the entire human population needs.[1] Wind power is renewable and there is no way we can run out of it (since wind energy originates from the sun). Wind turbines are incredible space-efficient. The largest of them generate enough electricity to power 600 U.S. homes.[2] Wind power only accounts for about 2.5% of total worldwide electricity production, but is growing at a promising rate of 25% per year (2010).[3] Prices have decreased over 80% since 1980 and are expected to keep decreasing.[4] The operational costs associated with wind power are low. Good domestic potential: Residential wind turbines yields energy savings and protects homeowners from power outages. Cons of Wind Power Wind is a fluctuating (intermittent) source of energy and is not suited to meet the base load energy demand unless some form of energy storage is utilized (e.g. batteries, pumped hydro). The manufacturing and installation of wind turbines requires heavy upfront investments – both in commercial and residential applications. Wind turbines can be a threat to wildlife (e.g. birds, bats). Noise is regularly reported as a problem by neighboring homes. How wind turbines look (aesthetics) is a legitimate concern for some people. • ## Question: Why do we resemble our parents? Posted in: Biology | Date: 12/03/2018 ### Answer: A pair of alleles is called a genotype. A dominant trait is the trait that will appear in the offspring over the recessive trait received from the other parent. ... We resemble our parents because of genes we inherit from them. We get genes from both of our parents. • ## Question: Write about Fibre Fineness. Posted in: Fashion Designing | Date: 12/03/2018 ### Answer: Fineness is one of the three most important fibre characteristics. The fineness determines how many fibres are present in the cross-section of a yarn of given thickness. Additional fibres in the cross-section provide not only additional strength, but also a better distribution in the yarn. Thirty fibres are needed at the minimum in the yarn cross-section, but there are usually over 100. • ## Question: Can a vector be positive or negative? Posted in: Physics | Date: 12/03/2018 ### Answer: Two vectors are equal if they have the same magnitude and the same direction. Just like scalars which can have positive or negative values, vectors can also be positive or negative. A negative vector is a vector which points in the direction opposite to the reference positive direction. • ## Question: What are the pros and cons of biomass energy? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Pros of Biomass Energy 1. Renewable: Biomass energy is a renewable resource. The principal positive about biomass energy is that it creates power by utilizing renewable assets. These assets may be wood waste, tree buildup, handled wood pellets or urban waste. As a rule, biomass energy plants utilize leftover wood that comes from existing logging or sawmill ventures. 2. Dependency on Fossil Fuels is Reduced: It replaces other fuel sources. In all cases, the fuel might be immediately replaced. By utilizing natural materials to deliver power, there is less interest for power created by non-renewable assets, for example, coal and gas. The entire purpose of utilizing renewable energy is to facilitate the reliance on sources that are harming nature’s domain in such a large number of ways. 3. Carbon Neutral: It doesn’t produce carbon. The distinction between using biomass fuel rather than coal or gas is that the carbon that is discharged was already part of nature because of the plant. At the point when coal or gas is utilized it is expelled starting from the earliest stage it has been sequestered for a large number of years. 4. Widely Available: Biomass energy is widely available all over the world. Organic waste in the form of dead leaves, grass and trees, animal carcasses are available in abundance and can be used to produce biomass energy. This in another way is good as the amount of waste that could have gone to landfills can be used as a source of energy. As long as organic matter from plants and animals is going to exist, we are never going to run out of biomass energy. 5. Can be Used in Many Forms: Biomass can be used to create different products from different forms of organic matter. It can be used to produce methane gas, biodiesel and other biofuels. It can also be used directly as heat or to generate electricity using a steam turbine. 6. Helps Reduce Waste: It helps with waste management. Consistently we create huge amounts of solid waste. This waste involves biodegradable waste, recyclable waste, along with dangerous toxic waste. Biomass energy uses this waste so that it’s no longer sitting in landfills. Cons of Biomass Energy 1. Not Totally Clean When Burned: The biggest contention against biomass as a clean energy is the pollution that is created from burning the wood and other natural materials. Sometimes, they’re as bad as the pollution that comes from coal and other types of energy resources. There are a number of different compounds that come from burning biomass. Even though biomass energy is considered to be renewable, it is hard to claim it is a clean or efficient power energy. 2. Can Lead to Deforestation: Wood is a major source of biomass energy. To produce considerable amount of power, large amount of wood and other waste products have to be burned. The desire to produce energy on a large scale can lead to deforestation that would destroy the homes of large number of plants and animals. 3. In-efficient: Biodiesel product like Ethanol which is produced by biomass is relatively inefficient as compared to gasoline. It has to be mixed with gasoline so that it can be used in combustion engines. Apart from that, long term usage of Ethanol can be harmful to the engines. 4. Requires Lot of Space: It’s hard to find a plant that is in a convenient place. Many times, biomass energy plants are found in urban areas, which means that they are causing more traffic in those areas and they are causing more pollution, which seems to be more of a problem than an actual help. 5. Expensive: The last problem that often comes up is how expensive this process is. The production of biomass plants is incredibly expensive and, in some cases, the costs are not worth the benefits. Transport and resource gathering expenses are high and will be continually needed every day. When you compare the process of biomass energy to fossil fuels, you find that the cost is actually much higher. • ## Question: What are the pros and cons of nuclear power? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Pros of Nuclear Energy 1. Low Pollution: Nuclear power also has a lot fewer greenhouse emissions. It has been determined that the amount of greenhouse gases have decreased by almost half because of the prevalence in the utilization of nuclear power. Nuclear energy has the least effect on nature since it doesn’t discharge any gasses like methane and carbon dioxide, which are the primary “greenhouse gasses.” There is no unfavorable impact on water, land or any territories because of the utilization of nuclear power, except in times where transportation is utilized. 2. Low Operating Costs: Nuclear power produces very inexpensive electricity. The cost of the uranium, which is utilized as a fuel in this process, is low. Also, even though the expense of setting up nuclear power plants is moderately high, the expense of running them is quite low low. The normal life of nuclear reactor is anywhere from 40-60 years, depending on how often it is used and how it is being used. These variables, when consolidated, make the expense of delivering power low. Even if the cost of uranium goes up, the impact on the cost of power will be that much lower. 3. Reliability: It is estimated that with the current rate of consumption of uranium, we have enough uranium for another 70-80 years. A nuclear power plant when in the mode of producing energy can run uninterrupted for even a year. As solar and wind energy are dependent upon weather conditions, nuclear power plant has no such constraints and can run without disruption in any climatic condition. There are sure monetary focal points in setting up nuclear power plants and utilizing nuclear energy in lieu of traditional energy. It is one of the significant sources of power all through the country. The best part is that this energy has a persistent supply. It is broadly accessible, there is a lot in storage, and it is believed that the supply is going to last much, much longer than that of fossil fuels that are used in the same capacity. 4. More Proficient Than Fossil Fuels: The other primary point of interest of utilizing nuclear energy is that it is more compelling and more proficient than other energy sources. A number of nuclear energy innovations have made it a much more feasible choice than others. They have high energy density as compared to fossil fuels. The amount of fuel required by nuclear power plant is comparatively less than what is required by other power plants as energy released by nuclear fission is approximately ten million times greater than the amount of energy released by fossil fuel atom. This is one the reason that numerous nations are putting a lot of time and money into nuclear power.What’s nuclear power’s greatest benefit, above any other benefit that we may explore? It doesn’t rely on fossil fuels and isn’t influenced by fluctuating oil and gas costs. Coal and natural gas power plants discharge carbon dioxide into the air, which causes a number of environmental issues. With nuclear power plants, carbon emissions are insignificant. 5. Renewable?: Nuclear energy is not renewable resource. Uranium, the nuclear fuel that is used to produced nuclear energy is limited and cannot be produced again and again on demand. On the other hand, by using breeder and fusion reactors, we can produce other fissionable element. One such element is called plutonium that is produced by the by-products of chain-reaction. Also, if we know how to control atomic fusion, the same reactions that fuel the sun, we can have almost unlimited energy. cons-nuclear-energy Cons of Nuclear Energy 1. Environmental Impact: One of the biggest issues is environmental impact in relation to uranium. The process of mining and refining uranium hasn’t been a clean process. Actually transporting nuclear fuel to and from plants represents a pollution hazard. Also, once the fuel is used, you can’t simply take it to the landfill – it’s radioactive and dangerous. 2. Radioactive Waste Disposal: As a rule, a nuclear power plant creates 20 metric tons of nuclear fuel per year, and with that comes a lot of nuclear waste. When you consider each nuclear plant on Earth, you will find that that number jumps to approximately 2,000 metric tons a year. The greater part of this waste transmits radiation and high temperature, implying that it will inevitably consume any compartment that holds it. It can also cause damage to living things in and around the plants. Nuclear power plants create a lot of low-level radioactive waste as transmitted parts and supplies. Over time, used nuclear fuel decays to safe radioactive levels, however this takes a countless number of years. Even low level radioactive waste takes hundreds of years to achieve adequate levels of safety. 3. Nuclear Accidents: The radioactive waste produced can pose serious health effects on the lives of people as well as the environment. The Chernobyl accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine was the worst nuclear accident in the history. Its harmful effects on humans and ecology can still be seen today. Then there was another accident that happened in Fukushima in Japan. Although the casualties were not that high, but it caused serious environmental concerns. 4. High Cost: At present, the nuclear business let waste cool for a considerable length of time before blending it with glass and putting away it in enormous cooled, solid structures. This waste must be kept up, observed and watched to keep the materials from falling into the wrong hands and causing problems. These administrations and included materials cost cash – on top of the high expenses needed to put together a plant, which may make it less desirable to invest in. It requires permission from several international authorities and it is normally opposed by the people who live in that region. • ## Question: What are synovial joints and discribe its types? Posted in: Biology | Date: 12/03/2018 ### Answer: A synovial joint, also known as diarthrosis, joins bones with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articulating surfaces. The synovial cavity/joint is filled with synovial fluid. The six types of synovial joints are the pivot, hinge, saddle, plane, condyloid, and ball-and-socket joints. Pivot joints are found in your neck vertebrae, while hinge joints are located in your elbows, fingers, and knees. Saddle and plane joints are found in your hands. • ## Question: What are phototatic movements and chemotatic movements? Posted in: Biology | Date: 12/03/2018 ### Answer: Paratonic Movements of Locomotion or Tactic Movements. They are locomotory movements of complete cells or organelles in response to external stimuli. (i) Phototaxis (Phototactic Movement). It is locomotion in response to direction and intensity of light. Chemotaxis (from chemo- + taxis) is the movement of an organism in response to a chemical stimulus. Somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment • ## Question: What is osmoregulation in plants and describe its tpyes in details? Posted in: Biology | Date: 12/03/2018 ### Answer: Osmoregulation is the active regulation of the osmotic pressure of bodily fluids to maintain the homeostasis of the body's water content; that is it keeps the body's fluids from becoming too dilute or too concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution the more water wants to go into the solution. The pressure that must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water. Two major types of osmoregulation are osmoconformers and osmoregulators. Osmoconformers match their body osmolarity to their environment . It can either be active or passive. Most marine invertebrates are osmoconformers, although their ionic composition may be different to that of seawater. • ## Question: What is hypertonic,hypotonic and isotonic environment? Posted in: Biology | Date: 12/03/2018 ### Answer: Isotonic, Hypotonic, and Hypertonic Solutions Water moves readily across cell membranes through special protein-lined channels, and if the total concentration of all dissolved solutes is not equal on both sides, there will be net movement of water molecules into or out of the cell. Whether there is net movement of water into or out of the cell and which direction it moves depends on whether the cell’s environment is isotonic, hypotonic, or hypertonic. Cells in Isotonic Solutions When two environments are isotonic, the total molar concentration of dissolved solutes is the same in both of them. When cells are in isotonic solution, movement of water out of the cell is exactly balanced by movement of water into the cell. A 0.9% solution of NaCl (saline) is isotonic to animal cells. When exposing animal tissues to solutions, it is common to use an isotonic solution such as Ringer's buffered saline so as to prevent osmotic effects and consequent damage to cells. Cells in Hypotonic Solutions Hypotonic comes from the Greek "hypo," meaning under, and "tonos," meaning stretching. In a hypotonic solution the total molar concentration of all dissolved solute particles is less than that of another solution or less than that of a cell. Cells in Hypertonic Solutions Hypertonic comes from the Greek "hyper," meaning over, and "tonos," meaning stretching. In a hypertonic solution the total molar concentration of all dissolved solute particles is greater than that of another solution, or greater than the concentration in a cell. • ## Question: How is nuclear energy released by the fission process? How is this energy conver... Posted in: Physics | Date: 12/03/2018 ### Answer: In a nuclear reactor this reaction is caused by the heat generated in the process of nuclear fission. Enriched uranium gives off energy through nuclear fission. ... The first step in producing electrical energy is enabling the water in the reactor core that contains the uranium bundle to expand into steam. These neutrons continue to hit other 235U atoms so that fission continues to occur. This is called a chain reaction. The chain reaction occurs inside a controlledenvironment – in the reactor core. The heat released from the reaction is used toheat water into steam, which in turn is used to generate electricity. • ## Question: What are the two advantages and two disadvantages of hydel power? Posted in: Physics | Date: 12/03/2018 ### Answer: Advantages Hydropower is a fueled by water, so it's a clean fuel source. Hydropower doesn't pollute the air like power plants that burn fossil fuels, such as coal or natural gas. Hydropower is a domestic source of energy, produced in the United States. Hydropower relies on the water cycle, which is driven by the sun, thus it's a renewable power source. Hydropower is generally available as needed; engineers can control the flow of water through the turbines to produce electricity on demand. Disadvantages Fish populations can be impacted if fish cannot migrate upstream past impoundment dams to spawning grounds or if they cannot migrate downstream to the ocean. Upstream fish passage can be aided using fish ladders or elevators, or by trapping and hauling the fish upstream by truck. Downstream fish passage is aided by diverting fish from turbine intakes using screens or racks or even underwater lights and sounds, and by maintaining a minimum spill flow past the turbine. Hydropower can impact water quality and flow. Hydropower plants can cause low dissolved oxygen levels in the water, a problem that is harmful to riparian (riverbank) habitats and is addressed using various aeration techniques, which oxygenate the water. Maintaining minimum flows of water downstream of a hydropower installation is also critical for the survival of riparian habitats. Hydropower plants can be impacted by drought. When water is not available, the hydropower plants can't produce electricity. • ## Question: How does humidity affect the human body? Posted in: Geography | Date: 12/03/2018 ### Answer: When the air has a high moisture content, as is the case in humid weather, this sweat cannot evaporate, leaving our bodies feeling hot and sticky. To cool off, our bodies must work even harder. This results in excessive sweating, increased rate and depth of blood circulation and increased respiration. • ## Question: Which planet has the thinnest atmosphere? Posted in: Geography | Date: 12/03/2018 ### Answer: Mercury ha thinnest atmosphere. • ## Question: Which is the thinnest layer of the atmosphere? Posted in: Geography | Date: 12/03/2018 ### Answer: thermosphere is the thinnest layer of the atmosphere. • ## Question: What is the thinnest layer on Earth? Posted in: Geography | Date: 12/03/2018 ### Answer: The crust is the thinnest layer of the Earth, amounting for less than 1% of our planet's volume. • ## Question: What is the thickest layer of the Earth's atmosphere? Posted in: Geography | Date: 12/03/2018 ### Answer: The troposphere is the first layer above the surface and contains half of the Earth's atmosphere. • ## Question: What is the strongest neodymium magnet? Posted in: Physics | Date: 12/03/2018 ### Answer: Grade N42 or higher are powerful neodymium magnet. • ## Question: How electricity and magnetism are related? Posted in: Physics | Date: 12/03/2018 ### Answer: Electricity and magnetism are closely related. Flowing electrons produce a magnetic field, and spinning magnets cause an electric current to flow. Electromagnetism is the interaction of these two important forces. • ## Question: What is Rutherford's experiment called? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Rutherford's Gold Foil Experiment proved the existance of a small massive center to atoms, which would later be known as the nucleus of an atom. Ernest Rutherford, Hans Geiger and Ernest Marsden carried out their Gold Foil Experiment to observe the effect of alpha particles on matter. • ## Question: What was Bohr's experiment called? Posted in: Chemistry | Date: 12/03/2018 ### Answer: To overcome this difficulty, Niels Bohr proposed, in 1913, what is now called the Bohr model of the atom. He suggested that electrons could only have certain classical motions: Electrons in atoms orbit the nucleus. ... The Bohr model of an atom was based upon Planck's quantum theory of radiation. • ## Question: Are protons and neutrons the same? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Atoms are made of extremely tiny particles called protons, neutrons, and electrons. Protons and neutrons are in the center of the atom, making up the nucleus. The charge on the proton and electron are exactly the same size but opposite. • ## Question: What conclusions were drawn from the gold foil experiment? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Conclusion of Rutherford's scattering experiment: Most of the space inside the atom is empty because most of the α-particles passed through the gold foil without getting deflected. • ## Question: What are the different types of electricity? Posted in: Physics | Date: 12/03/2018 ### Answer: There are two types of Electricity, Static Electricity and Current Electricity. Static Electricity is made by rubbing together two or more objects and making friction while Current electricity is the flow of electric charge across an electrical field. • ## Question: What are the different types of power generation? Posted in: Physics | Date: 12/03/2018 ### Answer: Heat (thermal) energy generated from: fossil fuels; coal. petroleum. natural gas. solar thermal energy. geothermal energy. nuclear energy. Potential energy from falling water in a hydroelectric facility. Wind energy. Solar electric from solar (photovoltaic) cells. Chemical energy from: fuel cells. batteries. • ## Question: What are the different Coloured bins for? Posted in: Biology | Date: 12/03/2018 ### Answer: Your 3 coloured bins take different waste: your blue bin is for recyclable waste. your brown bin is for kitchen and garden waste. your green or grey bin is for non-recyclable waste. • ## Question: What is the most magnetic material in the world? Posted in: Physics | Date: 12/03/2018 ### Answer: iron cobalt • ## Question: How are protons neutrons and electrons arranged to form an atom? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Atoms consist of electrons surrounding a nucleus that contains protons and neutrons. Neutrons are neutral, but protons and electrons are electrically charged. Protons have a relative charge of +1, while electrons have a relative charge of -1. The number of protons in an atom is called its atomic number. • ## Question: What are the seven wastes? Posted in: Biology | Date: 12/03/2018 ### Answer: The seven wastes consist of: Overproduction. Simply put, overproduction is to manufacture an item before it is actually required. ... Waiting. Whenever goods are not moving or being processed, the waste of waiting occurs. ... Transporting. ... Inappropriate Processing. ... Unnecessary Inventory. ... Unneces • ## Question: Where is the strongest magnet in the world? Posted in: Physics | Date: 12/03/2018 ### Answer: The world's strongest magnet has been created and sits in the National High Magnetic Field Laboratory at Florida State University. Neodymium magnets are the strongest rare earth magnets and the strongest magnets • ## Question: How are magnets used to generate electricity? Posted in: Physics | Date: 12/03/2018 ### Answer: A magnetic field pulls and pushes electrons in some objects near them to make them move. Metals, like copper, have electrons that are moved easily and can be readily moved from their orbits. If a magnet is moved quickly through a coil of copper wire, electrons move and electricity is made • ## Question: What are the main objectives of waste management? Posted in: Biology | Date: 12/03/2018 ### Answer: In general, the project brings: Contribution to the overall sustainability of the area. Improvement of overall waste management in the area. Increased recycling levels and reduction of organic waste in landfills. Obtaining a quality compost to be used as an organic amendment that contributes to improve soil fertility. • ## Question: Why is it important to dispose of waste correctly? Posted in: Biology | Date: 12/03/2018 ### Answer: Proper waste disposal is critical due to the fact that certain types of wastes can be hazardous and can contaminate the environment if not handled properly. These types of waste also have the potential to cause disease or get into water supplies. Rotting garbage is also known to produce harmful gases that mix with the air and can cause breathing problems in people. • ## Question: What are the 4 R's? Posted in: Biology | Date: 12/03/2018 ### Answer: A number of waste prevention techniques are available, and they are commonly summarized as the so-called 4Rs: reduction, reuse, recycling and recovery. • ## Question: Which part of the magnet is positive? Posted in: Physics | Date: 12/03/2018 ### Answer: When magnets are used in magnetic therapy, the poles are often referred to as being positive or negative. Generally, the South pole is termed positive, and the North negative. • ## Question: What are the six signs of a chemical reaction? Posted in: Chemistry | Date: 12/03/2018 ### Answer: The following are indicators of chemical changes: Change in Temperature. Change in Color. Noticeable Odor (after reaction has begun) Formation of a Precipitate. Formation of Bubbles. • ## Question: What is the difference between physical and chemical changes? Posted in: Chemistry | Date: 12/03/2018 ### Answer: A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed. • ## Question: What are the similarities between electricity and magnetism? Posted in: Physics | Date: 12/03/2018 ### Answer: Electricity and magnetism are closely related. Flowing electrons produce a magnetic field, and spinning magnets cause an electric current to flow. Electromagnetism is the interaction of these two important forces. • ## Question: Why is it important to have Waste Management? Posted in: Biology | Date: 12/03/2018 ### Answer: The importance of proper waste management. ... When trash is disposed of properly, we are able to prevent less pollution in the air, which can help with improve public health. When you use proper liners and containers for your trash, you are preventing toxic materials from entering the environment • ## Question: How does electricity and magnetism affect each other? Posted in: Physics | Date: 12/03/2018 ### Answer: They both deal with the movement of electric charges like the electrons that flow through wires, that we know as electricity. Basically, the flow of electricity through a wire creates magnetic fields, and certain types of magnetic fields (they have to change with time) cause the flow of electricity. • ## Question: Which is an example of a chemical change? Posted in: Chemistry | Date: 12/03/2018 ### Answer: The formation of rust on iron is a chemical change. • ## Question: How do you dispose of waste? Posted in: Biology | Date: 12/03/2018 ### Answer: It is used to dispose of solid, liquid and gaseous waste. It is recognized as a practical method of disposing of certain hazardous waste materials (such as biological medical waste). Incineration is a controversial method of waste disposal, due to issues such as emission of gaseous pollutants. Incineration is a waste treatment process that involves the combustion of organic substances contained in waste materials. Incineration and other high-temperature waste treatment systems are described as "thermal treatment". Incineration of waste materials converts the waste into ash, flue gas and heat. • ## Question: Are electricity and magnetism the same thing? Posted in: Physics | Date: 12/03/2018 ### Answer: Electricity and magnetism are essentially two aspects of the same thing, because a changing electric field creates a magnetic field, and a changing magnetic field creates an electric field. (This is why physicists usually refer to "electromagnetism" or "electromagnetic" forces together • ## Question: What is an example of a physical property? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Examples of physical properties are: color, smell, freezing point, boiling point, melting point, infra-red spectrum, attraction (paramagnetic) or repulsion (diamagnetic) to magnets, opacity, viscosity and density. • ## Question: Which is an example of a physical change? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Examples of Physical changes: ... Ice melting involves a change from a solid to a liquid and the substances maintain the properties of water because the molecules never change. • ## Question: Why are telescopes better than our eyes? Posted in: Physics | Date: 12/03/2018 ### Answer: Telescopes and their cameras are useful because they can gather far more light than can the human eye. Telescopes are also useful because they can distinguish two objects at a greater distance than can the human eye. • ## Question: What are the different optical instruments? Posted in: Physics | Date: 12/03/2018 ### Answer: A microscope. ... An example using the microscope. ... Telescopes. ... Resolving power. ... X-ray diffraction • ## Question: What are some examples of optical devices? Posted in: Physics | Date: 12/03/2018 ### Answer: An optical device is a device that creates, manipulates, or measures electromagnetic radiation. There are many kinds of optical devices, such as binoculars, lasers‎, microscopes‎, telescopes‎… And other optical devices used in the telecom fields, like fiber optic transceivers, fiber optic cables, fiber converters, etc. • ## Question: What are the properties of a Semimetal? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Metalloids often have the following properties: could be dull or shiny. conducts heat and electricity, but not as well as metals. good semiconductors. usually malleable. usually ductile. can both gain and lose electrons in reactions. • ## Question: What is an alloy metal? Posted in: Chemistry | Date: 12/03/2018 ### Answer: An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by a metallic bonding character. An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions) • ## Question: What does the Himalayas mean? Posted in: Geography | Date: 12/03/2018 ### Answer: A mountain system of south-central Asia extending about 2,400 km (1,500 mi) through Kashmir, northern India, southern Tibet, Nepal, and Bhutan. The Himalayas include nine of the world's ten highest peaks, including Mount Everest. • ## Question: What is the coinage metals? Posted in: Chemistry | Date: 12/03/2018 ### Answer: A Group 11 element is one in the series of elements in group 11 (IUPAC style) in the periodic table, consisting of transition metals which are the traditional coinage metals of copper (Cu), silver (Ag), and gold (Au) • ## Question: What is the oldest civilization in the world? Posted in: Geography | Date: 12/03/2018 ### Answer: Mesopotamian is considered to be oldest civilization in the world. • ## Question: Which elements are the metalloids? Posted in: Chemistry | Date: 12/03/2018 ### Answer: The Metalloids are: Boron. Silicon. Germanium. Arsenic. Antimony. Tellurium. Polonium. • ## Question: What happens when two wave crests meet? Posted in: Physics | Date: 12/03/2018 ### Answer: When the crests or troughs of two interfering waves meet, their amplitudes add together. This principle is known as constructive interference. The interference of waves causes the medium to take on a shape that results from the net effect of the two individual waves upon the particles of the medium. • ## Question: What is an actinide metal? Posted in: Chemistry | Date: 12/03/2018 ### Answer: The Actinide series contains elements with atomic numbers 89 to 103 and is the third group in the periodic table. The series is the row below the Lanthanide series, which is located underneath the main body of the periodic table. Lanthanide and Actinide Series are both referred to as Rare Earth Metals. • ## Question: Which is the smallest country in Europe? Posted in: Geography | Date: 12/03/2018 ### Answer: Vatican City is the smallest country in the europe. • ## Question: What is a wave interference? Posted in: Physics | Date: 12/03/2018 ### Answer: Wave interference is the phenomenon that occurs when two waves meet while traveling along the same medium. The interference of waves causes the medium to take on a shape that results from the net effect of the two individual waves upon the particles of the medium. • ## Question: What are the lanthanide elements? Posted in: Chemistry | Date: 12/03/2018 ### Answer: The lanthanides include the metals cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu) • ## Question: What mountain range splits Europe and Asia? Posted in: Geography | Date: 12/03/2018 ### Answer: Ural Mountains, which form the boundary between Europe and Asia. • ## Question: Which rivers flow from India to Pakistan? Posted in: Geography | Date: 12/03/2018 ### Answer: The three rivers - Indus, Jhelum and Chenab flow from india to pakistan. • ## Question: Do sound waves travel faster in water or air? Posted in: Physics | Date: 12/03/2018 ### Answer: In water, the particles are much closer together, and they can quickly transmit vibration energy from one particle to the next. This means that the sound wave travels over four times faster than it would in air, but it takes a lot of energy to start the vibration • ## Question: What is the main river in India? Posted in: Geography | Date: 12/03/2018 ### Answer: Brahmaputra River System. ... Ganga River System. ... Yamuna River System. ... Narmada River System. ... Tapti River System. ... Godavari River System. ... Krishna River System. • ## Question: What do you mean by normal incidence? Posted in: Physics | Date: 12/03/2018 ### Answer: The condition in which a wave-front is parallel to an interface, such that the ray path is perpendicular (normal) to the surface. The angle of incidence is zero called as "normal incidence." • ## Question: Which is the smallest mountain in the world? Posted in: Geography | Date: 12/03/2018 ### Answer: Mount Wycheproof, the world's smallest registered mountain. Located in Australia's Terrick Terrick Range, Mount Wycheproof stands 486 ft (148 meters to the rest of the world) above sea level. • ## Question: What is the fifth highest mountain in the world? Posted in: Geography | Date: 12/03/2018 ### Answer: Makalu is the fifth highest mountain in the world. • ## Question: What is meant by photonic? Posted in: Physics | Date: 12/03/2018 ### Answer: Photonics: The branch of technology concerned with the properties and transmission of photons, for example in fibre optics. • ## Question: Which rivers flow from Himalaya? Posted in: Geography | Date: 12/03/2018 ### Answer: There are three major Himalayan rivers such as: The Ganga, The Brahmaputra and The Indus. • ## Question: How does Hess's law work? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Hess's law states that energy changes are state functions. ... Energy (enthalpy) changes in chemical reactions are the same, regardless whether the reactions occur in one or several steps. The total energy change in a chemical reaction is the sum of the energy changes in its many steps leading to the overall reaction. • ## Question: Which mountains are between Spain and France? Posted in: Geography | Date: 12/03/2018 ### Answer: The Pyrenees mountain range separates the Iberian Peninsula from the rest of Europe, stretching more than 430km between Spain and France and rising higher than 3,400m in elevation. • ## Question: What is a simple definition of entropy? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Entropy is also a measure of the number of possible arrangements the atoms in a system can have. In this sense, entropy is a measure of uncertainty or randomness. ... Thermodynamic entropy is part of the science of heat energy. It is a measure of how organized or disorganized energy is in a system of atoms or molecules • ## Question: What is a good example of entropy? Posted in: Chemistry | Date: 12/03/2018 ### Answer: A campfire is an example of entropy • ## Question: What is Ural effervescent powder used for? Posted in: Geography | Date: 12/03/2018 ### Answer: Ural is a pleasantly flavouredeffervescent drink which provides relief from painful burning symptoms of urinary Tract Infections. Ural helps to neutralize the acid in the urinary tract while assisting in eliminating organisms that cause infection • ## Question: What is the Hess's law? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Hess's Law of Constant Heat Summation (or just Hess's Law) states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes. This law is a manifestation that enthalpy is a state function • ## Question: What is the meaning of entropy in thermodynamics? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Entropy is one of the consequences of the second law of thermodynamics.. Entropy is the measure of disorder: the higher the disorder, the higher the entropy of the system. Reversible processes do not increase the entropy of the universe. • ## Question: What is the chemical kinetics? Posted in: Chemistry | Date: 12/03/2018 ### Answer: Chemical kinetics is the study and discussion of chemical reactions with respect to reaction rates, effect of various variables, re-arrangement of atoms, formation of intermediates etc. There are many topics to be discussed, and each of these topics is a tool for the study of chemical reactions. By the way, the study of motion is called kinetics, from Greek kinesis, meaning movement. At the macroscopic level, we are interested in amounts reacted, formed, and the rates of their formation. At the molecular or microscopic level, the following considerations must also be made in the discusion of chemical reaction mechanism. Molecules or atoms of reactants must collide with each other in chemical reactions. The molecules must have sufficient energy (discussed in terms of activation energy) to initiate the reaction. In some cases, the orientation of the molecules during the collision must also be considered. • ## Question: What is the meaning of Ural? Posted in: Geography | Date: 12/03/2018 ### Answer: a mountain range in the W Russian Federation, extending N and S from the Arctic Ocean to near the Caspian Sea, forming a natural boundary between Europe and Asia. Highest peak, Mt. Narodnaya, 6214 feet (1894 meters). Expand. Also called Urals. • ## Question: What country are the Ural Mountains located in? Posted in: Geography | Date: 12/03/2018 ### Answer: the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan • ## Question: What is the difference between voltage and current? Posted in: Physics | Date: 13/03/2018 ### Answer: 1. Voltage is the difference in potential between two points 2. Current is the rate of flow of electricity across a given element. 3. Voltage divided by current is the resistance of the element. 4. Whether a person dies from electrocution is based on the current and not the voltage. 5. Voltage and Current multiplied is power • ## Question: Is it better to have higher voltage? Posted in: Physics | Date: 13/03/2018 ### Answer: A higher voltage means a lower current for the same amount of power. A lower current means smaller components and thinner wires, thus making it cheaper and more efficient. ... • ## Question: What is the function of a resistor in a circuit? Posted in: Physics | Date: 13/03/2018 ### Answer: A resistor is an electrical component that limits or regulates the flow of electrical current in an electronic circuit. Resistors can also be used to provide a specific voltage for an active device such as a transistor. • ## Question: What is the different between a cell and a battery? Posted in: Physics | Date: 13/03/2018 ### Answer: The difference between a cell and a battery is that a cell is a single unit that converts chemical energy into electrical energy, and a battery is a collection of cells. ... Aggregating cells into a battery increases the electrical voltage they produce. • ## Question: What is the difference between a fuel cell and a battery? Posted in: Physics | Date: 13/03/2018 ### Answer: A fuel cell is different from a battery cell in that reactants are constantly supplied to a fuel cell making it an open system whereas a battery cell is a closed system that stores the reactants within it. A fuel cell works as long as fuel is supplied to it whereas a battery cell requires regular replacements. • ## Question: Where are simple cells? Posted in: Physics | Date: 13/03/2018 ### Answer: Special chemical reactions which occur inside the electrical cell, result in oxidation and reduction of the substances inside the cell. This produces electrical energy. Normal batteries work like this. Some electrical cells produce electricity without using chemical energy. • ## Question: How does a simple cell produce electricity? Posted in: Physics | Date: 13/03/2018 ### Answer: Special chemical reactions which occur inside the electrical cell, result in oxidation and reduction of the substances inside the cell. This produces electrical energy. Normal batteries work like this. Some electrical cells produce electricity without using chemical energy. • ## Question: How does a battery work in simple terms? Posted in: Physics | Date: 13/03/2018 ### Answer: The cathode and anode (the positive and negative sides at either end of a traditional battery) are hooked up to an electrical circuit. The chemical reactions in the battery causes a build up of electrons at the anode. This results in an electrical difference between the anode and the cathode. • ## Question: What is an electric cell made of? Posted in: Physics | Date: 13/03/2018 ### Answer: Electric cell is a device that converts chemical energy to electrical energy. Cell comprises of two electrodes and an electrolyte. Electrodes are made of materials that participate im chemical reaction with the electrolyte. There are two kind of chemical reactions happening within the cell at ,oxidation and reduction. Oxidation implies the electrode material loses electron and positive ions dissolves into the electrolyte. This happens at one electrode( called anode) and this electron can flow out if the anode to external conducting wire provided there is a strong pulling force( called reduction potential) at the other electrode where this electron is accepted by the ion and deposits as metal in the electrode (called cathode). This two half cell reaction when combined (i.e oxidation and reduction) is called redox chemical reaction. This is responsible for the flow of electrons in the external circuit which can be used to drive different electrical load. • ## Question: What does the voltage tell you? Posted in: Physics | Date: 13/03/2018 ### Answer: Electricity is the movement of electrons. Electrons create charge, which we can harness to do work. ... Voltage is the difference in charge between two points. Current is the rate at which charge is flowing. Resistance is a material's tendency to resist the flow of charge (current). • ## Question: What is the difference between an electric cell and a battery? Posted in: Physics | Date: 13/03/2018 ### Answer: Difference Between Cell and Battery. The cell and battery both store the chemical energy and then transforms the stored chemical energy into an electrical energy. One of the major difference between the cell and the battery is that the cell is the single unit, whereas the battery is the group of cells • ## Question: What is a simple cell? Posted in: Physics | Date: 13/03/2018 ### Answer: A simple cell is a device that converts chemical energy into electrical energy. A simple electric cell consists of two electrodes (two different metals) and an electrolyte solution (acid or alkali solution or salt solution) • ## Question: How does a electric cell work? Posted in: Physics | Date: 13/03/2018 ### Answer: More specifically: during a discharge of electricity, the chemical on the anode releases electrons to the negative terminal and ions in the electrolyte through what's called an oxidation reaction. Meanwhile, at the positive terminal, the cathode accepts electrons, completing the circuit for the flow of electrons. • ## Question: What is the function of a cell in an electrical circuit? Posted in: Physics | Date: 13/03/2018 ### Answer: Its main function is to turn on or off the power of electricity flowing through wires. WIRES. Wires are used to join parts of a circuit. Electricity flows through wires. Its main function is to provide electrical items the power they need to work, provided by battery. • ## Question: What is a cell in an electrical circuit? Posted in: Physics | Date: 13/03/2018 ### Answer: Cell is a device used to power electrical circuits. It has two terminals; positive and negative. The terminal marked negative is the source of electrons, that when connected to a circuit delivers energy. We can take the example of a normal torch battery. A battery is a combination of multiple cells • ## Question: Isotopes of an element differ in the number of ............. in their nuclei. Posted in: Chemistry | Date: 13/03/2018 ### Answer: Isotopes of an element will contain the same number of protons and electrons but will differ in the number of neutrons they contain. • ## Question: The mass of a hydrogen atom is ............. kg. Posted in: WBJEE | Date: 13/03/2018 ### Answer: 1.6737236 × 10^-27 kg • ## Question: Why Metals are good conductors of electricity? Posted in: Physics | Date: 13/03/2018 ### Answer: Heat conduction in metals. The electrons in piece of metal can leave their atoms and move about in the metal as free electrons. ... This kinetic energy is transferred from hot parts of the metal to cooler parts by the free electrons. These move through the structure of the metal, colliding with ions as they go. • ## Question: Which device is used to break an electric circuit? Posted in: Physics | Date: 13/03/2018 ### Answer: A switch is an electric device that is used to complete or break an electric circuit. If the switch is 'ON', then a current can flow through the circuit • ## Question: What does the word ‘Aye’ mean in English? Posted in: English | Date: 10/04/2018 ### Answer: Aye means 'YES' • ## Question: Please give me the English word for AVAMANAM. Posted in: English | Date: 10/04/2018 ### Answer: Avamanan means "Shame" • ## Question: How liquor ammonia is different from liquid ammonia? Posted in: Chemistry | Date: 10/04/2018 ### Answer: Liquor ammonia is a solution of ammonia in water, whereas liquid ammonia is a compressed form of gasesous ammonia which is stored in cylinders in liquid form. • ## Question: What are four basic spheres found on or above the earth? Posted in: Geography | Date: 11/04/2018 ### Answer: Hydrosphere Lithosphere Atmosphere Biosohere • ## Question: In which way Sarnath is associated with Lord Buddha ? Posted in: Geography | Date: 11/04/2018 ### Answer: He preached his first sermon there. • ## Question: The Indus Valley people had contacts with Posted in: Geography | Date: 11/04/2018 ### Answer: Mesopotamia • ## Question: Path length is a Posted in: Physics | Date: 11/04/2018 ### Answer: Scalar • ## Question: The position of an object moving in a straight line can be specified with refere... Posted in: Physics | Date: 11/04/2018 ### Answer: Answer is D A conveniently choosen origin • ## Question: Which form of energy will a body possess placed at the top of hill? Posted in: Biology | Date: 11/04/2018 ### Answer: Potential Energy • ## Question: Which of the following does NOT constitute 90% of dry weight of any food? Posted in: Biology | Date: 11/04/2018 ### Answer: Fibres • ## Question: Who is known as the father of human anatomy? Posted in: Biology | Date: 11/04/2018 ### Answer: Andreas Vesalius • ## Question: What is the full form of GMO? Posted in: Biology | Date: 11/04/2018 ### Answer: Genetically Modified Organism • ## Question: Narmada and Tapi flow through which type of valley? Posted in: Geography | Date: 11/04/2018 ### Answer: Rift valley • ## Question: Which gland secretes the growth hormone? Posted in: Biology | Date: 11/04/2018 ### Answer: Pituitary Gland • ## Question: Which country having the largest population in Africa? Posted in: Geography | Date: 11/04/2018 ### Answer: Nigeria • ## Question: What is meant by the term 'Sericulture'? Posted in: Geography | Date: 11/04/2018 ### Answer: cultivation of silkworm for silk production • ## Question: What are the three ranges of the Himalayas? Posted in: Geography | Date: 11/04/2018 ### Answer: Himadri, Himachal, Shivalik • ## Question: In which areas are the Mangrove Forest found? Posted in: Geography | Date: 11/04/2018 ### Answer: Sunderban • ## Question: In which layer of the atmosphere ozone layer is located? Posted in: Biology | Date: 11/04/2018 ### Answer: Stratosphere • ## Question: Which valley is called as 'paradise on the earth'? Posted in: Geography | Date: 11/04/2018 ### Answer: Kashmir Valley • ## Question: What does the term ‘Vishram’ mean, in English? Posted in: Business English | Date: 11/04/2018 ### Answer: vishram in english would 'rest'. • ## Question: What does DNA stands for? Posted in: Biology | Date: 11/04/2018 ### Answer: Deoxyribo nucleic acid • ## Question: What does ATP stand for? Posted in: Biology | Date: 11/04/2018 ### Answer: Adenosine Triphosphate • ## Question: What is the colour of dry cobalt chloride paper? Posted in: Biology | Date: 11/04/2018 ### Answer: Blue • ## Question: What are the three examples of circular motion? Posted in: Physics | Date: 11/04/2018 ### Answer: Earth Rotation A spining Top A rotating shaft • ## Question: Which hormone is secreted by beta-cells of islets of Langerhans? Posted in: Biology | Date: 11/04/2018 ### Answer: Insulin • ## Question: What is an example of rotational motion? Posted in: Physics | Date: 11/04/2018 ### Answer: Earth rotation A spining Top • ## Question: What should come in place of the question mark (?) in the following number serie... Posted in: Mathematics | Date: 11/04/2018 ### Answer: Answer will be 1. • ## Question: What the outer part of the kidney is called that containing the Bowman's capsule... Posted in: Biology | Date: 11/04/2018 ### Answer: Renal. Cortex • ## Question: What is the energy currency of a cell? Posted in: Biology | Date: 11/04/2018 ### Answer: energy currency of a cell is ATP as it privides energy to body • ## Question: Which cytoplasmic organelle found only in an animal cell? Posted in: Biology | Date: 11/04/2018 ### Answer: centrosome • ## Question: Which gland has both endocrine and exocrine functions? Posted in: Biology | Date: 11/04/2018 ### Answer: Pancreas Gland • ## Question: Which part of the brain is concerned with memory? Posted in: Biology | Date: 11/04/2018 ### Answer: Cerebrum • ## Question: What is an example of translational motion? Posted in: Physics | Date: 11/04/2018 ### Answer: A ball sliding on the floor • ## Question: Which chemical substances obtained from certain micro-organisms that destroy har... Posted in: Biology | Date: 11/04/2018 ### Answer: Antibiotics • ## Question: What is the site of lite reaction in the cells of a leaf? Posted in: Biology | Date: 11/04/2018 ### Answer: Thylakoid • ## Question: What does NADP stands for? Posted in: Biology | Date: 11/04/2018 ### Answer: Nicotinamide Adenine Dinucleotide Phosphate • ## Question: Which kind of animal tissue found lining the respiratory organs? Posted in: Biology | Date: 11/04/2018 ### Answer: Ciliated epithelium • ## Question: Which part of the eye responsible for its shape? Posted in: Biology | Date: 11/04/2018 ### Answer: Sclera • ## Question: Wild ass is found in which place of India? Posted in: Geography | Date: 11/04/2018 ### Answer: Rann of kacch, Gujrat • ## Question: What is the technical term of the Plasma devoid of fibrinogen? Posted in: Biology | Date: 11/04/2018 ### Answer: that is called 'Serum'. • ## Question: Which pressure is responsible for the movement of water molecules across the cor... Posted in: Biology | Date: 11/04/2018 ### Answer: Turgor Pressure • ## Question: Which part of the ovary produces progesterone? Posted in: Biology | Date: 11/04/2018 ### Answer: Corpus luteum • ## Question: Which gland in the skin that secretes sebum? Posted in: Biology | Date: 11/04/2018 ### Answer: Sebaceous gland • ## Question: What is the stage where chromosomes lie on the equator of the achromatic spindle... Posted in: Biology | Date: 11/04/2018 ### Answer: Metaphase • ## Question: What is the full forms of NADP? Posted in: Biology | Date: 11/04/2018 ### Answer: Nicotinamide Adenine Dinucleotide Phosphate • ## Question: Which blood vessel carries oxygenated blood to the liver? Posted in: Biology | Date: 11/04/2018 ### Answer: Hepatic Artery • ## Question: Which disease is associated with the attack of microbe on the lungs? Posted in: Biology | Date: 11/04/2018 ### Answer: Tuberculosis • ## Question: What is IUCN stands for? Posted in: Biology | Date: 11/04/2018 ### Answer: IUCN Stands for International Union for Conservation of nature • ## Question: Which type of muscle tissue is exclusively in the heart? Posted in: Biology | Date: 11/04/2018 ### Answer: myocardium- cardiac muscle • ## Question: Which is the most popular continent? Posted in: Geography | Date: 11/04/2018 ### Answer: Asia • ## Question: The Ajanta Caves were built during the period of Posted in: Geography | Date: 11/04/2018 ### Answer: Guptas period • ## Question: What is the thickest layer of the earth? Posted in: Geography | Date: 11/04/2018 ### Answer: The thickest layer of earth is Mantle. • ## Question: What is the strongest magnetic material? Posted in: Physics | Date: 11/04/2018 ### Answer: Neyodymium Magnets • ## Question: The number of proper subsets of the set {1, 2, 3} is Posted in: Mathematics | Date: 11/04/2018 ### Answer: option C i. e. 6 • ## Question: The Term "line of action" in animation means? Posted in: Animation | Date: 11/04/2018 ### Answer: option C • ## Question: The name of the command that you should use to create a copy of your object insi... Posted in: Animation | Date: 11/04/2018 ### Answer: Duplicate • ## Question: With respect to the definition of an allied industry, which is an allied industr... Posted in: AMITE | Date: 11/04/2018 ### Answer: Option B i. e. Packaging industry • ## Question: Which of the following is untrue? Posted in: Biology | Date: 11/04/2018 ### Answer: option C is untrue • ## Question: Which sentence is untrue with respect to the human body? Posted in: Biology | Date: 11/04/2018 ### Answer: Option A i. e. unconsumed water broken • ## Question: Path length is defined as - Posted in: Physics | Date: 11/04/2018 ### Answer: Option is B • ## Question: What is the most spoken language in Asia? Posted in: Geography | Date: 11/04/2018 ### Answer: Chineese and English • ## Question: What is the most common biofuel? Posted in: Chemistry | Date: 11/04/2018 ### Answer: Ethanol fuel • ## Question: Is Biogas a biofuel? Posted in: Chemistry | Date: 11/04/2018 ### Answer: yes biogas is a type of biofuel. • ## Question: When is the dot product of two vectors 0? Posted in: Physics | Date: 11/04/2018 ### Answer: when two vectors are perpendicular to each other, the dot product will be zero as cosine 90 is zero. • ## Question: Do ethanol fires produce heat? Posted in: Chemistry | Date: 11/04/2018 ### Answer: yes ethanol produces large amount of heat as a combustion process. • ## Question: Is ethanol and biodiesel the same? Posted in: Chemistry | Date: 11/04/2018 ### Answer: no both are not same as ethanol is a alcoholic where biodiesel is a type of biofuel. • ## Question: Organisms which respire in absence of air are called _________. Posted in: Physics | Date: 11/04/2018 ### Answer: Anaerobes • ## Question: Breathing is a ________ process while respiration is a _______ process. Posted in: Physics | Date: 11/04/2018 ### Answer: Option A • ## Question: What are the two types of electrical current? Posted in: Physics | Date: 11/04/2018 ### Answer: Alternating Current & Direct current • ## Question: What is an example of a physical change in chemistry? Posted in: Chemistry | Date: 11/04/2018 ### Answer: Melting of Ice is an example of physical change. • ## Question: What metals are used in everyday life? Posted in: Chemistry | Date: 11/04/2018 ### Answer: Iron, Aluminium, Copper, Stainless steel • ## Question: What is an example of a metalloid? Posted in: Chemistry | Date: 11/04/2018 ### Answer: Germanium • ## Question: What is the most famous mountain in the Alps? Posted in: Geography | Date: 11/04/2018 ### Answer: Mont Blanc • ## Question: Which state has the most energy solid liquid or gas? Posted in: Physics | Date: 11/04/2018 ### Answer: solid state • ## Question: What is inside of a neutron? Posted in: Chemistry | Date: 11/04/2018 ### Answer: Neutron are neutral. • ## Question: Which instrument is used to measure gas pressure? Posted in: Physics | Date: 11/04/2018 ### Answer: Braometer • ## Question: What happens to the density when the pressure increases? Posted in: Physics | Date: 11/04/2018 ### Answer: density of gases is directly proportional to the change in pressure. • ## Question: What is smaller than an atom? Posted in: Chemistry | Date: 11/04/2018 ### Answer: electron, proton and neutron • ## Question: What is the value for R in the ideal gas law? Posted in: Physics | Date: 11/04/2018 ### Answer: The value of R is 8.314 j/mol. k • ## Question: Can we see an atom? Posted in: Chemistry | Date: 11/04/2018 ### Answer: yes atom can be seen with electorn microscope. • ## Question: What is the difference between an atom and an ion? Posted in: Chemistry | Date: 11/04/2018 ### Answer: Atom can be neutral where ion is charge of an atom. • ## Question: Do liquids have more kinetic energy than solids? Posted in: Physics | Date: 11/04/2018 ### Answer: yes liquid has more kinetic energy compared to solid as atoms are more free to move in liquid. • ## Question: What causes a woman to die while giving birth? Posted in: Biology | Date: 11/04/2018 ### Answer: Post partum hemorrage abd anaemia. • ## Question: What are the diseases of the reproductive system? Posted in: Biology | Date: 11/04/2018 ### Answer: warts syphillus gonnoreah • ## Question: The number of electrons in the outer most orbits of carbon atom is Posted in: AMITE | Date: 11/04/2018 ### Answer: there will be 4 electrons in its outermost shell. • ## Question: Is \(CH_3CH_2COOH$$ an acid or a base?

Posted in: Chemistry | Date: 11/04/2018

it is a base due to presence of OH in it.

• ## Question: Is Potassium a base or acid?

Posted in: Chemistry | Date: 11/04/2018

potassium is a simply metal.

• ## Question: What are some examples of noise pollution?

Posted in: Biology | Date: 11/04/2018

loudspeakers vehicles honk

• ## Question: Is calcium carbonate a base or acid?

Posted in: Chemistry | Date: 11/04/2018

calcium. carbonate is a salt.

• ## Question: Is $$KNO_3$$ an acid or base?

Posted in: Chemistry | Date: 11/04/2018

it is an acid.

• ## Question: Is soap an acid or a base?

Posted in: Chemistry | Date: 11/04/2018

it is an base.

• ## Question: What is the approximate pH of saliva secretion?

Posted in: Biology | Date: 11/04/2018

pH of saliva is 7.4

• ## Question: Where are salivary glands located in humans?

Posted in: Biology | Date: 11/04/2018

salivary gland is located in mucosal tissues in oral cavity.

• ## Question: What are the main functions of saliva?

Posted in: Biology | Date: 11/04/2018

saliva consist of enzyme amylase which work on starch and break down starch into simple sugar.

• ## Question: The nitrogenous waste in Amphibia is

Posted in: Biology | Date: 11/04/2018

option is C i. e. Urea

• ## Question: Which of the following is not a ‘Lewis acid’ AlCl$$_3$$, BeCl$$_2$$,...

Posted in: Chemistry | Date: 11/04/2018

sncl4

• ## Question: Which is a non-metal liquid?

Posted in: Chemistry | Date: 11/04/2018

The bromine is a non metal liquid which is liquid at room temperature.

• ## Question: Can you drink alcohol while taking ibuprofen?

Posted in: Chemistry | Date: 11/04/2018

No it is not a good idea to drink alcohol while taking ibuprofen.

• ## Question: What is the best anti-inflammatory medication over the counter?

Posted in: Chemistry | Date: 11/04/2018

Aspirin

• ## Question: How much ibuprofen can you take in 24 hours?

Posted in: Chemistry | Date: 11/04/2018

there are many factor on which it depends like age and weight.

• ## Question: What is an example of Newton's third law of motion?

Posted in: Physics | Date: 14/04/2018

newton third laws implys that there will be equal and opposite reaction for every action. for ex. - a body lying on the ground

• ## Question: What does a switch do in an electric circuit?

Posted in: Physics | Date: 14/04/2018

switch breaks the links between two points and thereby stoping the flow of electric current in any circuit.

• ## Question: How do you calculate the power?

Posted in: Physics | Date: 14/04/2018

electrical power, p=VxI or, p=I^2XR

• ## Question: Who is the author of The Rivals ?

Posted in: English | Date: 14/04/2018

Richard Brinsley Sheridan

• ## Question: What is the use of friction?

Posted in: Physics | Date: 14/04/2018

friction is a type of force which always acts in the opposite direction of motion. It helps in walking.

• ## Question: Is methanol a base or an acid?

Posted in: Chemistry | Date: 14/04/2018

methanol is acidic in nature.

• ## Question: Is laundry detergent a base or acid?

Posted in: Chemistry | Date: 14/04/2018

laundary detergent are basic in nature.

• ## Question: Is $$BaCl_2$$ a base or acid?

Posted in: Chemistry | Date: 14/04/2018

it is niether acid or base but it is a salt.

• ## Question: Is $$NH_4Cl$$ an acid base or salt?

Posted in: Chemistry | Date: 14/04/2018

it is a salt which obtained by neutralisation reaction of hydrochloric acid and ammonium hydroxide.

• ## Question: Is water a base?

Posted in: Chemistry | Date: 14/04/2018

water is neutral as pH value of water is 7.

• ## Question: Is Salt a base or an acid?

Posted in: Chemistry | Date: 14/04/2018

salt is neither acidic or basic as salt formed by neutralisation reaction of acid and base.

• ## Question: Is $$NaHCO_3$$ an acid or a base?

Posted in: Chemistry | Date: 14/04/2018

it is base as pH of solutuon will be more tha 7.it is a weak base.

• ## Question: Which is more acidic H$$_3$$PO$$_4$$ or H$$_3$$PO$$_3$$?

Posted in: Chemistry | Date: 14/04/2018

H3PO3 is more acidic in nature.

• ## Question: Is $$NH_4Cl$$ an acid or base or neutral?

Posted in: Chemistry | Date: 14/04/2018

NH4Cl ia niether base or acid as it is salt. it can be treated as neutral.

• ## Question: What does it mean when a woman has high testosterone?

Posted in: Biology | Date: 14/04/2018

she will be behaving as homosexuals.

• ## Question: Which is the longest west flowing river of the peninsular India?

Posted in: Geography | Date: 14/04/2018

longest west flowing river is Narmda.

• ## Question: What type of rocks is Deccan Plateau made of?

Posted in: Geography | Date: 14/04/2018

Igneous Rock

• ## Question: Who wrote The Mayor Of Casterbridge ?

Posted in: English | Date: 14/04/2018

Thomas hardy

• ## Question: The number of electrons in the outer most orbits of carbon atom is

Posted in: AIEEE | Date: 14/04/2018

since atomic number of carbon in 6. so it will be distributed as 2,4 so electrons in outermost is 4.

• ## Question: Process in which food substances are moved to rest of plant by phloem is known a...

Posted in: Biology | Date: 14/04/2018

Translocation

• ## Question: What is translatory motion with examples?

Posted in: Physics | Date: 14/04/2018

A ball rolling on floor.

• ## Question: What is apiculture?

Posted in: Biology | Date: 14/04/2018

apiculture is rearing and management of honeybees for commercial production of honey.

• ## Question: What is dialysis?

Posted in: Biology | Date: 14/04/2018

It is a process of removing excess water and waste from blood by using artifical machine when kidney is not functioning properly.

• ## Question: What is genetic engineering?

Posted in: Biology | Date: 14/04/2018

it is the direct manipulation of organims genome using biotechnology.

• ## Question: What is 'birth rate'?

Posted in: Biology | Date: 14/04/2018

it is the total number of live birth per 1000 of a population in a year.

• ## Question: Which techniques are used for controlling amounts of gaseous pollutants of our a...

Posted in: Biology | Date: 14/04/2018

Electrostatic precipitator and scrubber

• ## Question: What is meant by osmoregulation?

Posted in: Biology | Date: 14/04/2018

It is the maintenance of constant osmotic pressure in the fluids of an organism by the control of water and salt concentrations.

• ## Question: Which layers of the Earth is broken up into tectonic plates?

Posted in: Geography | Date: 14/04/2018

lithosphere

• ## Question: Which layer of the atmosphere contains the ionosphere?

Posted in: Geography | Date: 14/04/2018

Mesosphere contains ionosphere.

• ## Question: Which layer of atmosphere protects the earth from meteoroids?

Posted in: Geography | Date: 14/04/2018

Answer is Mesosphere which protects the earth from metroites.

• ## Question: Which way is counter clockwise right or left?

Posted in: Physics | Date: 14/04/2018

it is from left to right pattern i. e. in the opposite of rotation of clock.

• ## Question: Is Salt acidic or alkaline in the body?

Posted in: Chemistry | Date: 14/04/2018

salt is neutral in nature. salt is generally reaction of an acid and base.

• ## Question: Is lemon juice good for gout?

Posted in: Chemistry | Date: 14/04/2018

yes it si good for gout. since lemon contains vitamin C, it is a natural remedy of gout.

• ## Question: What are three examples of circular motion?

Posted in: Physics | Date: 14/04/2018

earth rotation satellite rotating on its orbit rotation of celing fan

• ## Question: Which layer of the earth is found directly above the Earth's core?

Posted in: Geography | Date: 14/04/2018

the layer found exactly above the earth vore is mantle.

• ## Question: What is the simplest living thing?

Posted in: Physics | Date: 14/04/2018

Mycoplasma

• ## Question: Which provides energy very slowly?

Posted in: Biology | Date: 14/04/2018

Fats

• ## Question: what is the meaning of linguist

Posted in: English | Date: 14/04/2018

linguist is someone who is skilled in many different languages or can say foreign languages

• ## Question: What is the unit for the magnitude of acceleration?

Posted in: Physics | Date: 14/04/2018

S. I. unit for accelration is m/s^2

• ## Question: What is the result of resolving a vector?

Posted in: Physics | Date: 14/04/2018

vector has two component after resolving it. i. e. horiozntal component and vertical component.

• ## Question: Is the magnitude always positive?

Posted in: Physics | Date: 14/04/2018

yes the magnitude is always positive as it is a physical quantity.

• ## Question: Can the magnitude of a vector be zero?

Posted in: Physics | Date: 14/04/2018

yes the magnitude of vector can be zero.

• ## Question: Is depletion of ozone layer harmful?

Posted in: Biology | Date: 14/04/2018

yes depletion of ozone layer is harmful because it protects earth from. reaching UV rays.

• ## Question: What is organic chemistry ?

Posted in: Chemistry | Date: 14/04/2018

organic chemsitry is the branch of chemistry which delas with the various reaction among organic compound and study various features among them.

• ## Question: Do gallstones ever go away?

Posted in: Biology | Date: 14/04/2018

yes gall stones can be removed by proper surgery only after getting opinion from doctor.

• ## Question: What are some things that use electromagnets?

Posted in: Physics | Date: 14/04/2018

Transformers Electric bells Motor and generators

• ## Question: What is an example of a hard magnetic material?

Posted in: Physics | Date: 14/04/2018

hard magnets are sometimes also referred as permanents magnet who retain their magnetism after being magnetised.

• ## Question: How long is the Appalachian mountain range?

Posted in: Geography | Date: 14/04/2018

it has been extended about 2000 to 3000 km

• ## Question: What is the value of g on Earth?

Posted in: AIEEE | Date: 16/04/2018

we consider value of earth as 9.81m/s^2.

• ## Question: How many lattice points are there in one unit cell of Face-centred tetragon...

Posted in: Chemistry | Date: 16/04/2018

There are 14 lattice points in fave centered tetragonal.

• ## Question: What would happen if there was no gravity on the moon?

Posted in: AIEEE | Date: 16/04/2018

there will be free fall on moon.

• ## Question: What is an example of an atom?

Posted in: Chemistry | Date: 19/04/2018

There are lots of types of atoms and those types are called elements. The element helium, for example, contains atoms with two protons in the nucleus. ... The element oxygen contains atoms with eight protons. And the element gold contains atoms with 79 protons.

• ## Question: What is an example of a molecule?

Posted in: Chemistry | Date: 19/04/2018

A molecule is two or more atoms bonded together chemically. An atom is the most basic unit of matter. When atoms are chemically bonded together with covalent bonds, molecules are formed. Molecules can be very small like watermolecules or extremely large like proteins such as hemoglobin.

• ## Question: What is made up of quarks?

Posted in: Chemistry | Date: 19/04/2018

A quark (/kwɔːrk, kwɑːrk/) is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei.

• ## Question: Who was the first to propose the idea of atoms?

Posted in: Chemistry | Date: 19/04/2018

Democritus was a Greek philosopher (470-380 B.C.) who is the father of modernatomic thought. He proposed that matter could NOT be divided into smaller pieces forever. John Dalton created the very first atomic theory.

• ## Question: How many atoms are there in a grain of sand?

Posted in: Chemistry | Date: 19/04/2018

Avogadro tells us that we have 6.023 x 10^23 SiO2 units per gram, so there would be 6.023 x 10^23 / 60≈ 1 x 10^22 SiO2 units in a gram of pure SiO2, and with SiO2 composed of 3 atoms, that puts us at 3 x 10^22 atoms per gram of SiO2. Now, a grain of sand does not weigh 1 gram.

• ## Question: What are some examples of a molecule?

Posted in: Chemistry | Date: 19/04/2018

H2O (water) N2 (nitrogen) O3 (ozone) CaO (calcium oxide) C6H12O6 (glucose, a type of sugar)

• ## Question: What are harmonics?

Posted in: Physics | Date: 19/04/2018

an overtone accompanying a fundamental tone at a fixed interval, produced by vibration of a string, column of air, etc. in an exact fraction of its length

• ## Question: What is inside of a quark?

Posted in: Chemistry | Date: 19/04/2018

Inside the Quark. ... They've found that an atom has a nucleus, that a nucleus contains protons and neutrons, and that those particles in turn are made of quarksand gluons--particles that bind quarks together. But most physicists believe quarksto be the smallest building blocks of matter.

• ## Question: Is there anything smaller than a quark? Please explain.

Posted in: Chemistry | Date: 19/04/2018

Composite subatomic particles (such as protons or atomic nuclei) are bound states of two or more elementary particles. For example, a proton is made of two upquarks and one down quark, while the atomic nucleus of helium-4 is composed of two protons and two neutrons.

• ## Question: What atoms make up muscle?

Posted in: Chemistry | Date: 19/04/2018

Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium

• ## Question: What happens when you try to split an atom?

Posted in: Chemistry | Date: 19/04/2018

when you split an atom there is a huge explosion. when an atom splits in half some of the matter in the atom is converted into energy. The broken pieses become atomsfor another element.

• ## Question: What is the Valency of zinc?

Posted in: Chemistry | Date: 19/04/2018

Notice that the outermost shell, which for zinc is the fourth shell, n=4 , has two electrons. This means that zinc can lose the two electrons located in the 4s-orbital to be become the Zn2+ cation. ... Therefore,zinc has only 2 valence electrons, both located in the 4s-orbital

• ## Question: What is the Valency of neon?

Posted in: Chemistry | Date: 19/04/2018

valency of neon is 0 because it has completely filled valence{outermost} shell i.e. 8 electrons and so it is stable.

• ## Question: What is efforescence? Give an example.

Posted in: Physics | Date: 19/04/2018

Efflorescence is a crystalline deposit of salts often seen on the surface of concrete, brick, stucco, or natural stone surfaces. It occurs when water is present on or in the masonry surface. It sparkles. It's white, sometimes with a grayish tint Copper(II) sulfate (bluestone) (CuSO4.5H2O) is a blue crystalline solid that when exposed to air, slowly loses water of crystallization from its surface to form a white layer of anhydrous copper(II) sulfate. Sodium carbonate deca hydrate (Na2CO3.10H2O) will lose water when exposed to air

• ## Question: How many atoms are there in a human cell?

Posted in: Chemistry | Date: 19/04/2018

it is that this is 100,000,000,000,000 or 100 trillion atoms. Interestingly, the number of cells in thehuman body is estimated to be about the same as the number of atoms in a human cell.

• ## Question: What does N C V stand for?

Posted in: Physics | Date: 19/04/2018

A nerve conduction velocity (NCV) test — also called a nerve conduction study (NCS) — measures how fast an electrical impulse moves through your nerve. ... During the test, your nerve is stimulated, usually with electrode patches attached to your skin. Two electrodes are placed on the skin over your nerve.

• ## Question: How is soap prepared?

Posted in: Chemistry | Date: 19/04/2018

soaps are sodium or potassium salts of long chain fatty acids. When triglycerides in fat/oil react with aqueous NaOH or KOH, they are converted into soap and glycerol. This is called alkaline hydrolysis of esters. Since this reaction leads to the formation of soap, it is called the Saponification process.

• ## Question: What is a torque?

Posted in: Physics | Date: 19/04/2018

Torque is the twisting force that tends to cause rotation. The point where the object rotates is known as the axis of rotation. Mathematically, torque can be written as T = F * r * sin(theta), and it has units of Newton-meters.

• ## Question: What is the formula for work?

Posted in: Physics | Date: 19/04/2018

Whenever 'work' is done energy is transferred from one place to another. The amount of work done is expressed in the equation: work done = force x distance.

• ## Question: What is the first order reaction?

Posted in: Chemistry | Date: 19/04/2018

First-order reaction may refer to: Order of reaction, in chemical kinetics, the power to which the concentration term of a certain reactant in the rate equation is raised. Rate equation#First-order reactions, a reaction that depends on the concentration of only one reactant.  In other words, in first-order reactions, the rate is proportional to the concentration of reactant A.

• ## Question: What is the first order reaction?

Posted in: Chemistry | Date: 19/04/2018

First-order reaction may refer to: Order of reaction, in chemical kinetics, the power to which the concentration term of a certain reactant in the rate equation is raised. Rate equation#First-order reactions, a reaction that depends on the concentration of only one reactant.  In other words, in first-order reactions, the rate is proportional to the concentration of reactant A.

• ## Question: What is a slow chemical reaction?

Posted in: Chemistry | Date: 19/04/2018

Slow reactions Chemical reactions that occur very slowly and can take a long time for completion are called slow reactions. Usually covalent compounds are involved in slow reactions. Some reactions can take days, weeks and months to complete; they are called very slow reactions.  The rusting of iron, the fermentation of sugar into alcohol, the chemical weathering of rocks, and the photosynthesis process in plants are slow chemical reactions

• ## Question: What is a fast reaction?

Posted in: Chemistry | Date: 19/04/2018

fast chemical reaction is one that occurs essentially instantaneously. Often times a fast reaction is used to measure the rate of a slow reaction. A way of understanding this is to imagine a slow reaction that you can't time because it is colorless before and after the reaction. You have no way of directly knowing how fast it reacted. Well what if you added some additional reactant that reacted with the product from the slow reaction to cause a color change? Then you have a slow reaction that you can time by measuring the color change in the fast reaction. This is just an example of how to use it.

• ## Question: What is the geography of Asia?

Posted in: Geography | Date: 19/04/2018

Asia is the largest of the world's continents, covering approximately 30 percent of the Earth's land area. It is also the world's most populous continent, with roughly 60 percent of the total population. ... Asia's physicalgeography, environment and resources, and humangeography can be considered separately Asia also has 60.4% of the world's population. There are deserts, tropical rain forests, and the highest mountains in the world. Asia's geography affects where people live and where they grow crops. Because of the physical features and climate, people in Asia can live on only a small part of the total land area.

• ## Question: What is the second order of reaction?

Posted in: Chemistry | Date: 19/04/2018

Second-Order Reactions. The simplest kind ofsecond-order reaction is one whose rate is proportional to the square of the concentration of one reactant. ... A second kind of second-order reactionhas a reaction rate that is proportional to the product of the concentrations of two reactants

• ## Question: Why is a reaction irreversible?

Posted in: Chemistry | Date: 19/04/2018

In an irreversible reaction, the reactants react to form the products, which cannot revert back into reactants. Inreversible reactions, as the reactants react with other reactants to form products, the products are reacting with other products to form reactants.

• ## Question: What is an atom?

Posted in: Chemistry | Date: 19/04/2018

Atoms are the basic building blocks of ordinary matter. ... Atoms are composed of particles called protons, electrons and neutrons. Protons carry a positive electrical charge, electrons carry a negative electrical charge and neutrons carry no electrical charge at all.

• ## Question: What are the most common types of waste?

Posted in: Biology | Date: 19/04/2018

Liquid Waste. Liquid waste is commonly found both in households as well as in industries. ... Solid Rubbish. Solid rubbish can include a variety of items found in your household along with commercial and industrial locations. ... Organic Waste. Organic waste is another common household. ... Recyclable Rubbish. ... Hazardous Waste

• ## Question: What is apiculture?

Posted in: Biology | Date: 19/04/2018

Apiculture is breeding honey bees for the production of honey and bees wax using modern scientific and commercial methods. The name apiculture is due to the scientific (generic) name of the honeybees which is 'Apis'. Bee culture or apiculture is practices throughout the world.

• ## Question: What is the meaning of ‘transport’?

Posted in: Geography | Date: 19/04/2018

Transport or transportation is the movement of humans, animals and goods from one location to another. Modes of transport include air, land (rail and road), water, cable, pipeline and space. ... Freighttransport has become focused on containerization, although bulk transport is used for large volumes of durable items.

• ## Question: What is meant by Retardation?

Posted in: Biology | Date: 19/04/2018

Negative acceleration is called retardation. If the velocity of a body is decreasing with respect to time, the acceleration is said to be negative. Retardation is the rate of decrease in velocity.

• ## Question: What is a pseudo second order reaction?

Posted in: Chemistry | Date: 19/04/2018

If the concentration of a reactant remains constant (because it is a catalyst or it is in great excess with respect to the other reactants), its concentration can be included in the rate constant, obtaining a pseudo–first-order (or occasionally pseudo–second-order) rate equation.

• ## Question: What is Proxemics in communication?

Posted in: Chemistry | Date: 20/04/2018

Basically, proxemics is the study of space and how we use it, how it makes us feel more or less comfortable, and how we arrange objects and ourselves in relation to space. The term was coined by the anthropologist Edward Hall. Hall was interested in understanding how humans use space incommunication.

• ## Question: What is persistence of hearing of a human ear?

Posted in: Physics | Date: 20/04/2018

Persistence of hearing of a human ear means how much time the sensation of any sound stay in our brain. For normal human ear the value is 0.1 s. Now If the persistence of hearing is increased or decreased compared to normalear ,it indicates the hearing loss of the human ear.

• ## Question: What is a spherical mirror? Neme the two types of spherical mirrors.

Posted in: Physics | Date: 20/04/2018

A spherical mirror is simply a piece cut out of a reflective sphere. Its center of curvature, C, is the center of the sphere it was cut from. R, the mirror's radius of curvature is the radius of the sphere. The focal point F (the point where parallel rays are focused) is located half the distance from the mirror to the center of curvature. The focal length, f, is:

focal length of a spherical mirror : f = R / 2

This is actually an approximation. Parabolic mirrors are really the only mirrors that focus parallel rays to a single point, but as long as the rays don't get too far from the principal axis then the equation above applies for spherical mirrors.

If the mirror's inside surface is reflective, the mirror is concave; if the outside is reflective, it's a convex mirror. Concave mirrors can form either real or virtual images, depending on where the object is. A convex mirror can only form virtual images. A real image is an image that the light rays from the object actually pass through; a virtual image is formed because the light rays can be extended back to meet at the image position, but they don't actually go through the image position.

• ## Question: What is the highest Mach speed ever recorded?

Posted in: Physics | Date: 20/04/2018

Guinness World Records recognized NASA's X-43A scramjet with a new world speed record for a jet-powered aircraft - Mach 9.6, or nearly 7,000 mph.

• ## Question: What is the speed of sound at 40000 feet?

Posted in: Physics | Date: 20/04/2018

he speed of sound is not a constant, but depends on altitude (or actually the temperature at that altitude). A plane flying Mach 1.0 at sea level is flying about 1225 km/h (661 Knots, 761 mph), a plane flying Mach 1.0 at 30000 ft is flying 1091 km/h (589 knots, 678 mph) etc.

• ## Question: What is apiculture ?

Posted in: Biology | Date: 20/04/2018

Apiculture is breeding honey bees for the production of honey and bees wax using modern scientific and commercial methods. The name apiculture is due to the scientific (generic) name of the honeybees which is 'Apis'. Bee culture or apiculture is practices throughout the world.

• ## Question: How does chlorophyll help in photosynthesis?

Posted in: Biology | Date: 20/04/2018

Chlorophyll is vital for photosynthesis, which allows plants to absorb energy from light. Chlorophyll molecules are arranged in and around photosystems that are embedded in the thylakoid membranes of chloroplasts. ... This pair effects the final function of chlorophylls, charge separation, leading to biosynthesis.

• ## Question: How does a biodiesel engine work?

Posted in: Chemistry | Date: 20/04/2018

biodiesel is an alternative or additive to standard diesel fuel that is made from biological ingredients instead of petroleum (or crude oil). Biodiesel is usually made from plant oils or animal fat through a series of chemical reactions.

Biodiesel is the name of a clean burning alternative fuel, produced from domestic, renewable resources. Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biodiesel blend. It can be used in compression-ignition (diesel) engines with little or no modifications.

• ## Question: What are the advantages of bio ethanol?

Posted in: Chemistry | Date: 20/04/2018

The use ofethanol-blended fuels such as E85 (85% ethanol and 15% gasoline) can reduce the net emissions of greenhouse gases by as much as 37.1%, which is a significant amount. You can use any plant for production of bioethanol, it only has to contain sugar and starch.

• ## Question: What are the properties of actinides?

Posted in: Chemistry | Date: 20/04/2018

Actinides share the following common properties:

All are radioactive. ... Actinides are highly electropositive. The metals tarnish readily in air. ... Actinides are very dense metals with distinctive structures. ... They react with boiling water or dilute acid to release hydrogen gas. Actinide metals tend to be fairly soft.

• ## Question: What is the formula for tension?

Posted in: Physics | Date: 20/04/2018

The tension on an object is equal to the mass of the object x gravitational force plus/minus the mass x acceleration Tension is nothing but the pulling force acting on the body when it is hanged to the objects like string, cable, chain etc. It is denoted by T (sometimes also denoted as Ft). If the tension is equal to weight of body T = W

• ## Question: What is an 180 degree rotation?

Posted in: Physics | Date: 20/04/2018

otation of a point through 180°, about the origin when a point M (h, k) is rotated about the origin O through 180° in anticlockwise or clockwise direction, it takes the new position M' (-h, -k).

• ## Question: What do you mean by rotational motion?

Posted in: Physics | Date: 20/04/2018

Rotational motion is more complicated than linear motion, and only the motion of rigid bodies will be considered here. A rigid body is an object with a mass that holds a rigid shape, such as a phonograph turntable, in contrast to the sun, which is a ball of gas. Many of the equations for the mechanics of rotating objects are similar to the motion equations for linear motion.

Angular velocity and angular acceleration

The angular displacement of a rotating wheel is the angle between the radius at the beginning and the end of a given time interval. The SI units are radians. The average angular velocity (ω, Greek letter omega), measured in radians per second, is

The angular acceleration (α, Greek letter alpha) has the same form as the linear quantity

• ## Question: What is the importance of dissolved air in water?

Posted in: Chemistry | Date: 20/04/2018

Just as we need air to breathe, aquatic organisms need dissolved oxygen to respire. It is necessary for the survival of fish, invertebrates, bacteria, and underwater plants. DO is also needed for the decomposition of organic matter.

• ## Question: Why is carbonic acid a dibasic acid?

Posted in: Chemistry | Date: 20/04/2018

A dibasic acid yields two free hydrogen ions in solution for each molecule of acid ionized or in other terms, has two replaceable hydrogen atoms. A simple example of adibasic acid is sulphuric acid (H2SO4). Other examples of dibasic acids are as follows i.e. Carbonic acid(H2CO3) and Oxalic acid (C2H4H2) etc.

• ## Question: What is rotational potential energy?

Posted in: Physics | Date: 20/04/2018

During linear motion, when a force is applied, the work it does gets converted to kinetic energy and there is no change in the potential energy. Similarly, duringrotational motion when a torque is applied to angularly accelerate a body, the work done by the torque leads to an increase in kinetic energy.

• ## Question: What is rotational potential energy?

Posted in: Physics | Date: 20/04/2018

During linear motion, when a force is applied, the work it does gets converted to kinetic energy and there is no change in the potential energy. Similarly, duringrotational motion when a torque is applied to angularly accelerate a body, the work done by the torque leads to an increase in kinetic energy.

• ## Question: What is the Reflectional symmetry?

Posted in: Physics | Date: 20/04/2018

A type of symmetry where one half is the reflection of the other half. You could fold the image and have both halves match exactly. Here my dog "Flame" has her face made perfectly symmetricalwith a bit of photo magic. The white line down the center is called the Line of Symmetry.

• ## Question: What are the different types of motion?

Posted in: Physics | Date: 20/04/2018

basic types of motion in mechanical systems:

Rotary motion is turning round in a circle, such as a wheel turning. Linear motion is moving in a straight line, such as on a paper trimmer. Reciprocating motion is moving backwards and forwards in a straight line, as in cutting with a saw.

• ## Question: Why rain water harvesting is important?

Posted in: Geography | Date: 20/04/2018

Rainwater harvesting is the accumulation and deposition of rainwater for reuse on-site, rather than allowing it to run off. ... Rain water is easily processed to providewater for domestic purposes. Many households already have water tanks or swimming pools to store rain water. There are many advantages of harvesting rainwater, some of which include:

It is absolutely free to use and a clean source of water. ... It is easy to install. ... It can be used for many different purposes. ... It is environmentally friendly. ... It is excellent for irrigation. ... It reduces the use of ground water.

• ## Question: What is translatory motion with examples?

Posted in: Physics | Date: 20/04/2018

The motion in which all the particles of a body move through the same distance in the same time is calledtranslatory motion. There are two types oftranslatory motions: rectilinear motion; curvilinearmotion. The examples for thetranslatory motion are: A man running. A bus moving. A dog walking. A ship sailing. Moving of a ball.Translatory motion

• ## Question: What are the six basic sources of electricity?

Posted in: Physics | Date: 20/04/2018

Primary energy sources take many forms, including nuclear energy, fossil energy -- like oil, coal and natural gas -- and renewable sources like wind, solar, geothermal and hydropower.

• ## Question: What was discovered in the gold foil experiment?

Posted in: Chemistry | Date: 20/04/2018

n 1910, a physicist from New Zealand, Ernest Rutherford performed an experiment known as Rutherford’s gold foil experiment. This experiment was determined to find out the structure of an atom. By this time it was discovered by J.J. Thomson that electrons are present in an atom and that they are negatively charged. So it was assumed that since an atom is neutral and electrons present are negatively charged, there should be some positive charge inside it that makes it neutral. So Rutherford worked under the discoveries and assumption of J.J. Thomson. He accepted J.J. Thomson’s model of an atom which was plum pudding model. According to the plum pudding model, there were negatively charged particles i.e. electrons embedded or suspended in a sphere of positive charge (electrons presented as plums inside the bowl of pudding) [Plum Pudding Model] Earnest Rutherford set up an apparatus and did an experiment that could confirm JJ Thomson’s model of an atom. But he ended up with some new facts in the structure of the atom. His experiment is as follows: Construction of his experiment: It has a radioactive source rich in positively charged heavy alpha particles inside a cube shaped thick lead box with a narrow opening.  [Alpha Scattering Experiment] The alpha particles were confined to a narrow beam by passing then through a lead sheet through a slit. An extremely thin gold foil was bombarded with the narrow beam of fast moving alpha particles. On bombarding the alpha particles were scattered in different directions with different angles and were detected by florescent rotatable detector which has a microscope and a screen coated with zinc sulphide. The whole experimental setup was placed in an evacuated chamber to prevent scattering by the air molecules. These particles after striking on the screen caused scintillations. Before performing this experiment it was assumed by Rutherford that most of the alpha particles would pass through the gold foil with less deflection. He assumed this on the basis of theory proposed by JJ Thomson. This was assumed because the alpha particles are heavy and the negative charge in the "plum pudding model" is widely spread. After performing his experiment he made observations:

Almost all the alpha particles did pass through the foil but Some alpha particles were deflected off at different angles as observed at the screen of the detector. Very few of the alpha particles (one or two) even bounced backwards after hitting the gold foil.

On the basis of these observations Rutherford made the following conclusions:

Since most of the alpha particles passed straight through the gold foil without any deflection, most of the space within the atoms is empty. Since some of the alpha particles (which are big in size) were deflected by large angles or bounced backwards, they must have approached some positively charged region responsible for the deflection. This positively charged region is now called the nucleus. As very few alpha particles undergone the deflection, it was concluded that the volume occupied by the central region ( nucleus ) is very small. Since alpha particles which are relatively denser, were deflected by the central volume of charge, it shows that almost the complete mass of the atom must be within the central volume.

• ## Question: What was Chadwick's experiment?

Posted in: Chemistry | Date: 20/04/2018

The discovery of the neutron and its properties was central to the extraordinary developments in atomic physics that occurred in the first half of the 20th century. Early in the century, Ernest Rutherford developed a crude model for the atom,[1]:188 [2] based on the gold foil experiment of Hans Geiger and Ernest Marsden. In this model, atoms had their mass and positive electric charge concentrated in a very small nucleus.[3] By 1920 chemical isotopes had been discovered, the atomic masses had been determined to be integer multiples of the mass of the hydrogen atom,[4] and the atomic number had been identified as the charge on the nucleus.[5]:§1.1.2 Throughout the 1920s, the nucleus was viewed as composed of combinations of protons and electrons, the two elementary particles known at the time, but that model presented several experimental and theoretical contradictions.[1]:298

The essential nature of the atomic nucleus was established with the discovery of the neutron by James Chadwick in 1932[6] and the determination that it was a new elementary particle, distinct from the proton.[7][8]:55

The uncharged neutron was immediately exploited as a new means to probe nuclear structure, leading to such discoveries as the creation of new radioactive elements by neutron irradiation (1934) and the fission of uranium atoms by neutrons (1938).[9] The discovery of fission led to the creation of both nuclear power and weapons by the end of World War II. Both the proton and neutron were presumed to be elementary particles until the 1960s when they were determined to be composite particles built from quarks.[10]

• ## Question: What is Conservation of mineral?

Posted in: Geography | Date: 20/04/2018

Minerals takes millions of years for the formation of minerals. Compared to the present rate of consumption, the replenishment rate of minerals is very slow. Hence, mineral resources are finite and non-renewable. Due to this, it is important that we conserve the mineral resources. So It is necessary to use mineral as per your need for mining industry. In India , several mining industry exporters are available , who exports & manufacture minerals for industrial uses

• ## Question: Explain Ferromagnetism:

Posted in: Chemistry | Date: 20/04/2018

A magnet made of alnico, an iron alloy, with its keeper. Ferromagnetism is the theory which explains how materials become magnets.

Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets. In physics, several different types of magnetism are distinguished. Ferromagnetism (including ferrimagnetism)[1] is the strongest type: it is the only one that typically creates forces strong enough to be felt, and is responsible for the common phenomena of magnetism in magnets encountered in everyday life. Substances respond weakly to magnetic fields with three other types of magnetism, paramagnetism, diamagnetism, and antiferromagnetism, but the forces are usually so weak that they can only be detected by sensitive instruments in a laboratory. An everyday example of ferromagnetism is a refrigerator magnet used to hold notes on a refrigerator door. The attraction between a magnet and ferromagnetic material is "the quality of magnetism first apparent to the ancient world,

• ## Question: Explain Paramagnetism:

Posted in: Chemistry | Date: 20/04/2018

Paramagnetism is a form of magnetism whereby certain materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, diamagnetic materials are repelled by magnetic fields and form induced magnetic fields in the direction opposite to that of the applied magnetic field.[1] Paramagnetic materials include most chemical elements and some compounds;[2] they have a relative magnetic permeability slightly greater than 1 (i.e., a small positive magnetic susceptibility) and hence are attracted to magnetic fields. The magnetic moment induced by the applied field is linear in the field strength and rather weak. It typically requires a sensitive analytical balance to detect the effect and modern measurements on paramagnetic materials are often conducted with a SQUID magnetometer.

• ## Question: Explain Ferrimagnetism:

Posted in: Chemistry | Date: 20/04/2018

In physics, a ferrimagnetic material is one that has populations of atoms with opposing magnetic moments, as in antiferromagnetism; however, inferrimagnetic materials, the opposing moments are unequal and a spontaneous magnetization remains.

• ## Question: Explain Antiferromagnetism:

Posted in: Chemistry | Date: 20/04/2018

In materials that exhibit antiferromagnetism, the magnetic moments of atoms or molecules, usually related to the spins of electrons, align in a regular pattern with neighboring spins (on different sublattices) pointing in opposite directions.

• ## Question: Why does leather get hardened after tanning?

Posted in: Chemistry | Date: 20/04/2018

First reason is the aging and drying. The leather gets stiffer through lack of maintenance and use. It has not been re-oiled or used in a very long time causing a lack of movement of the leather fibres. Another reason can be the shrinkage of the Leather by heat.

• ## Question: What are essential mineral elements?

Posted in: Biology | Date: 20/04/2018

Nitrogen, phosphorus, potassium, calcium,magnesium, sulfur, boron, chlorine, iron,manganese, zinc, copper, molybdenum, andnickel. Other elements that have been proposed as candidates for essential or beneficial elements includechromium, vanadium, and titanium, although strong evidence is lacking at this time

• ## Question: Explain F-centres:

Posted in: Chemistry | Date: 20/04/2018

An F-center, Farbe center or color center (from the original German Farbzentrum; Farbe means color, and zentrum center) is a type of crystallographic defect in which an anionic vacancy in a crystal is filled by one or more unpaired electrons.

• ## Question: What do you understand by “Donnan Equilibrium?

Posted in: Biology | Date: 20/04/2018

The Gibbs–Donnan effect (also known as theDonnan's effect, Donnan law, Donnan equilibrium, or Gibbs–Donnan equilibrium) is a name for the behaviour of charged particles near a semi-permeable membrane that sometimes fail to distribute evenly across the two sides of the membrane.

• ## Question: Explain Frenkel defect:

Posted in: Chemistry | Date: 20/04/2018

A Frenkel defect or dislocation defect is a type ofdefect in crystalline solids wherein an atom is displaced from its lattice position to an interstitial site, creating a vacancy at the original site and an interstitial defect at the new location without any changes in chemical properties.

Frenkel defect arises when some of the ions of the lattice occupy interstitial sites leaving lattice vacant. This defect generally found in ionic crystals where anion is much larger in size than the cation. Due to this density does not change in overall composition of the crystal. Examples:Zns, AgBr.

• ## Question: Explain Schottky defect:

Posted in: Chemistry | Date: 20/04/2018

A Schottky defect is a type of point defect in a crystal lattice named after Walter H. Schottky. In non-ionic crystals it means a lattice vacancy defect. In ionic crystals, the defect forms when oppositely charged ions leave their lattice sites, creating vacancies. Schottky defect arise when equal number of cations and anions are missing from the lattice. It is a common defect in ionic compounds of high coordination number* where both cations and anions are of the same size. Due to this density of crystal decreases and begins to conduct electricity to a smaller extent.

• ## Question: What is the Magnocellular?

Posted in: Physics | Date: 20/04/2018

[Image result for magnocellular] Magnocellular cells, also called M-cells, are neurons located within the Adina magnocellular layer of the lateral geniculate nucleus of the thalamus. The cells are part of the visual system. They are termed "magnocellular" since they are characterized by their relatively large size compared to parvocellular cells.

• ## Question: Where is the LGN?

Posted in: Physics | Date: 20/04/2018

They wrap around the midbrain and cross the medial surface of the temporal lobe, and 80% of them then terminate in a synaptic relay called the lateral geniculate nucleus (LGN), located in the dorsal part of the thalamus. The LGN is thus the major target for each optic tract.

• ## Question: What is the simplest form of a cell?

Posted in: Physics | Date: 20/04/2018

Prokaryotic Cell: Structure, Reproduction and DNA Transfer. Evolved nearly 4 billion years ago, prokaryotic cell is the simplest form of cells which lack defined nucleus or membrane-bound nucleus as well as other membrane-bound cell organelles.

• ## Question: What do the hormones do?

Posted in: Biology | Date: 20/04/2018

Hormones are chemical messengers that travel throughout the body coordinating complex processes like growth, metabolism, and fertility. They can influence the function of the immune system, and even alter behavior. Before birth, they guide development of the brain and reproductive system.

• ## Question: What are the five main types of erosion?

Posted in: Biology | Date: 20/04/2018

Wind Erosion

Wind erosion, though it may be small where you live, can take quite a toll on areas of the world covered in desert. Wind erosion is simple... light objects, such as rocks and pebbles are carried by the wind and can hit landforms, eroding materials off them, that are carried off in the wind.

Glacier Erosion

Ice erosion, besides that of hail, comes mostly in the form of glacier erosion. Glaciers are giant bodies of ice that can pick up huge pieces of rock, some even as big as houses. A combination of the water, ice, and picked up sediment, create a powerful eroding machine.

The more sediment that's picked up, the greater the force of erosion. The erosion can smooth out areas that were once rugged and rocky. Glaciers can carry almost anything, and like sandpaper, the sediment just keeps increasing. Glaciers are such a powerful force that they can carve valleys, deposit moraines, or lead to the creation of landforms such as delta's (discussed later).

Sea Erosion

Erosion in the Sea also occurs. The salts and other chemicals can erode weak rocks on the coast, such as limestone and chalk. The eroded materials are carried up the shore by the means of a longshore drift

Waves crashing against the shore can create air pressure inside cracked rocks, that can eventually break them. Furthermore, if rocks, pebbles or sediment is carried in the waves, they can smash up against the shore and erode it even more.

Soil Erosion

Soil erosion pays the biggest price to farmers. Flooding, wind etc. can carry the topsoil away from farmlands, and make the soil unfertile. I will have more information in the pages ahead.

• ## Question: Describe the Fibrograph Instrument?

Posted in: Fashion Designing | Date: 20/04/2018

The original idea of the photoelectric scanning or Fibrograph method has been developed by Hertel in 1940 for testing cotton lint. This test method is much faster than the array method and is used widely in ﬁber laboratories for measuring fiber length and length distribution. These tests are performed with a Fibrograph instrument, which is a photoelectric device (ﬁg.).

In Fibrograph, ﬁber samples are presented in the form of a pair of carefully prepared fringes. The light transmitted through these fringes is monitored byphotoelectric current. The amount of light passing through the ﬁber sample is linearly proportional to the number of ﬁbers in the light path. The changes in the photoelectric current are recorded graphically in the form of a Fibrogramas shown in Fig. From this Fibrogram various length parameters of practical interest, such as span length, mean length (OM), upper-half mean length (OR) and index of uniformity, given as the ratio of OM to OR, can be analyzed.

[Shirley Photoelectric Modal Stapler]        [Fibrograph]

Preparation of Test Specimen

Test specimen can be prepared from the laboratory sample by on of the following method.

1) Hand Combing Method

Pick up a handful of cotton from the laboratory sample and separate it into two parts by pulling so as to expose a fresh surface of projecting ﬁbers. Holding one of the hand combs in one hand and the opened lump of cotton in the other, transfer some of the projecting ﬁbers on to the comb. Pick fresh lumps of cotton, and proceed in the same manner so that a pair of combs is ﬁlled with sufﬁcient quantity of ﬁbers drawn from 8 to 10 randomly picked lumps. Hold one comb in each hand, and untangle and parallelize the projecting ﬁbers by mutual combing. The pair of combed beards constitutes the test specimen.

2) Fibro-Sampler Method

Mount one of the ﬁbro-sample combs in the comb holder of the Fibro sampler, with the teeth uppermost. Place the laboratory sample in the cage and press it against the perforated surface. Maintain the pressure and rotate the sample holder round the drum counter-clockwise through 360°. Remove the loaded comb from the holder. Turn the sample in the cage to expose a fresh surface, and mount ﬁbers in one more comb. Either one or a pair of combed beards constitute the test specimen depending upon the model of the instrument being used.

Fibrogram:

Fibrogram is an arrangement of fibers from shortest to longest in terms of span lengths. Fibrogram test are required for determining the length uniformity of fibers in the sample of cotton.

At any instant in time, fibers caught by the roller nips will depend on the randomness of their overlapping lengths; therefore, not all the length of a given fiber projects into draft zone. The lengths that project into the draft zone are called the span lengths, and the cumulative frequency distribution of the span length gives the Fibrogram.

[Span length concept 1] [Span length concept 2]

Digital Fibrograph:

The digital fibrograph gives the tests results in digits or numerical form. Suppose In the 2.5% span the length is 1.14 inch while in the 50 percent span the length is 0.52 inch. The uniformity ratio is 46%.

[eqn digital fibrogram]

[Gigital fibrograph with fibrosampler]

Fibro sampler is used in later models to clamp the ﬁbers on the comb. Fiber sample is put inside the cylinder of sampler. Fiber comb, with 13 needles/inch, is rotated around the ﬁbro sampler, with pressure applied on the cotton, during which it picks up ﬁbers projecting from the holes of sampler. The instrument is consequently insensitive to the presence of very short fibres, and in practice the Fibrogram has its origin at a point representing a length of 0.15 inch (3.8 mm).

Digital Fibrogram may be analyzed graphically to yield various length parameters of interest to the producers and users of cotton. The tangent to the curve at its starting point A cuts OY at P and OX at M. Then OM is the mean length of the fibers in the original population longer than 0.15 inch (3.8 mm). If OP is bisected at Q and the tangent to the curve from Q cuts OX at R, then OR is the upper-half mean length, UHML, and the ratio of OM to OR is a valid index of uniformity.

[Fibrogram of Digital Fibrograph Machine]

(1319)

[Md Sohanur Rahman Sobuj]

Md Sohanur Rahman Sobuj

Co-founder , Admin & Author at Textile Study Center Student of Bangladesh University of Textiles (BUTex)/ Department: Apparel Engineering [Md Sohanur Rahman Sobuj] [Md Sohanur Rahman Sobuj][Md Sohanur Rahman Sobuj] [Md Sohanur Rahman Sobuj]

TAGS: DIGITAL FIBROGRAPH FIBROGRAPH METHOD PHOTOELECTRIC SCANNING METHOD   1.32KPREVIOUSEffective Length of Cotton Fiber NEXTSpan Length RELATED POSTS [shirley thickness guage machine]

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The original idea of the photoelectric scanning or Fibrograph method has been developed by Hertel in 1940 for testing cotton lint. This test method is much faster than the array method and is used widely in ﬁber laboratories for measuring fiber length and length distribution. These tests are performed with a Fibrograph instrument, which is a photoelectric device (ﬁg.).

In Fibrograph, ﬁber samples are presented in the form of a pair of carefully prepared fringes. The light transmitted through these fringes is monitored byphotoelectric current. The amount of light passing through the ﬁber sample is linearly proportional to the number of ﬁbers in the light path. The changes in the photoelectric current are recorded graphically in the form of a Fibrogramas shown in Fig. From this Fibrogram various length parameters of practical interest, such as span length, mean length (OM), upper-half mean length (OR) and index of uniformity, given as the ratio of OM to OR, can be analyzed.

[Shirley Photoelectric Modal Stapler]        [Fibrograph]

Preparation of Test Specimen

Test specimen can be prepared from the laboratory sample by on of the following method.

1) Hand Combing Method

Pick up a handful of cotton from the laboratory sample and separate it into two parts by pulling so as to expose a fresh surface of projecting ﬁbers. Holding one of the hand combs in one hand and the opened lump of cotton in the other, transfer some of the projecting ﬁbers on to the comb. Pick fresh lumps of cotton, and proceed in the same manner so that a pair of combs is ﬁlled with sufﬁcient quantity of ﬁbers drawn from 8 to 10 randomly picked lumps. Hold one comb in each hand, and untangle and parallelize the projecting ﬁbers by mutual combing. The pair of combed beards constitutes the test specimen.

2) Fibro-Sampler Method

Mount one of the ﬁbro-sample combs in the comb holder of the Fibro sampler, with the teeth uppermost. Place the laboratory sample in the cage and press it against the perforated surface. Maintain the pressure and rotate the sample holder round the drum counter-clockwise through 360°. Remove the loaded comb from the holder. Turn the sample in the cage to expose a fresh surface, and mount ﬁbers in one more comb. Either one or a pair of combed beards constitute the test specimen depending upon the model of the instrument being used.

Fibrogram:

Fibrogram is an arrangement of fibers from shortest to longest in terms of span lengths. Fibrogram test are required for determining the length uniformity of fibers in the sample of cotton.

At any instant in time, fibers caught by the roller nips will depend on the randomness of their overlapping lengths; therefore, not all the length of a given fiber projects into draft zone. The lengths that project into the draft zone are called the span lengths, and the cumulative frequency distribution of the span length gives the Fibrogram.

[Span length concept 1] [Span length concept 2]

Digital Fibrograph:

The digital fibrograph gives the tests results in digits or numerical form. Suppose In the 2.5% span the length is 1.14 inch while in the 50 percent span the length is 0.52 inch. The uniformity ratio is 46%.

[eqn digital fibrogram]

[Gigital fibrograph with fibrosampler]

Fibro sampler is used in later models to clamp the ﬁbers on the comb. Fiber sample is put inside the cylinder of sampler. Fiber comb, with 13 needles/inch, is rotated around the ﬁbro sampler, with pressure applied on the cotton, during which it picks up ﬁbers projecting from the holes of sampler. The instrument is consequently insensitive to the presence of very short fibres, and in practice the Fibrogram has its origin at a point representing a length of 0.15 inch (3.8 mm).

Digital Fibrogram may be analyzed graphically to yield various length parameters of interest to the producers and users of cotton. The tangent to the curve at its starting point A cuts OY at P and OX at M. Then OM is the mean length of the fibers in the original population longer than 0.15 inch (3.8 mm). If OP is bisected at Q and the tangent to the curve from Q cuts OX at R, then OR is the upper-half mean length, UHML, and the ratio of OM to OR is a valid index of uniformity.

• ## Question: Discuss about Grab Test Method?

Posted in: Fashion Designing | Date: 20/04/2018

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Textile Grab Test Equipment

[Textile Grab Test Fixture Diagram]

The most common tensile test used in the textile industry is called the grab test. The grab test method is a modification of a standard tensile test for use with woven and non woven textile fabrics that measures ultimate strength and elongation. A typical tensile test clamps the end of the specimen, which is effective when testing metals, plastics, and other traditional solid materials. However, this type of gripping introduces edge effects if used for textile materials, giving inaccurate tensile data and does not provide a correct measure of the bulk fabric material properties. The grab test eliminates edge effects by clamping the center of the sample width, away from the sample ends, and using jaws smaller than the sample width. As with all textile tests, alignment of the grip surfaces with the plane of the fabric sample is crucial for achieving accurate results. However, the orientation of the fabric in the sample is only significant if the material exhibits anisotropic material properties, which would give different strength values for off axis loading. Textile Grab Strength Test Standards In accordance with ASTM and ISO standards, data from grab test experiments is used to determine effective fabric strength, which is the fabric strength in a specific width together with the strength contributed by adjacent material. Popular grab test standards are ASTM D751 for coated fabrics, ASTM D1683 for woven apparel fabric seams, ASTM D2208 for soft, boarded, sueded, or embossed leather, ASTM D5034 for textile fabrics, and ISO 13934-2 for fabrics, and ISO 13935-2 for fabrics and made-up textiles, such as clothing apparel. Textiles tend to be difficult to test without slippage or jaw face breaks due to over- tightening. Pneumatic grips offer ease of use, productivity, and enhanced repeatability. Pneumatic action grips also allow the user to set clamp pressure. Common grab tests require special 25.4 mm x 50.8 mm (1 in x 2 in) front jaw faces, with the opposing jaw face at least as big. Grip pressure and specimen alignment are critical. Too much pressure produces premature breaks, and low pressure causes specimen slippage or breaks at or near the grip jaw faces. Slack correction is needed or the specimen is held too loosely in the grips at the start of the test. Tabletop tensile test machines are a good fit for textile tensile tests in general because they feature CRE (constant rate of extension or constant test speed) capabilities. They meet and exceed ASTM D76 textile test machine standards.

• ## Question: Write short notes on Fabric Abrasion Resistance

Posted in: Fashion Designing | Date: 20/04/2018

Abrasion resistance is the ability of a fabric to resist surface wear caused by flat rubbing contact with another material. There are two different test methods commonly used by the textile industry to assess abrasion resistance: Wyzenbeek and Martindale

• ## Question: What does Retinotopic organization mean?

Posted in: Physics | Date: 20/04/2018

Retinotopy (from Greek τόπος, place) is the mapping of visual input from the retina to neurons, particularly those neurons within the visual stream. For clarity, 'retinotopy' can be replaced with 'retinal mapping', and 'retinotopic' with 'retinally mapped'. Retinotopic Organization in Human Visual Cortex and the Spatial Precision of Functional MRI. Page 1. A method of using functional magnetic resonance imaging (fMRI) to measure retinotopic organizationwithin human cortex is described.

• ## Question: What is Rate Law in chemical kinetics?

Posted in: Chemistry | Date: 20/04/2018

According to the law of mass action, the rate of achemical reaction at a constant temperature depends only on the concentrations of the substances that influence the rate. ... Catalysts, which do not appear in the balanced overall chemical equation, can also influence reaction rate.

• ## Question: Explain in Analysis of sorter diagram?

Posted in: Fashion Study | Date: 20/04/2018

A representative sample is taken and the individual fibre length is measured. These values are arranged accordingly and the mean and coefficient of variation are calculated. This method is mainly used for the man made staple fibres as the variation in length is not much.

The fibres are straightened and placed on an oil plate and the individual length of fibres (around 300-500) is measured.

(A) Hand stapling method : (By trained classers):

Selecting a sample and preparing the fibres by hand doubling and drawing to give a fairly well straightened tuft of about ½ inch wide.

This is laid on flat black background and the staple length is measured.

The shorter fibres will lie in body of the tuft and extreme ends (tips) will not be the limits used for measurement of staple length.

The classer chooses the length where there are reasonably well defined edges.

Subjective in nature, so difference in results between classers.

(B) Comb Sorter Method:

• ## Question: What is meant by population composition?

Posted in: Geography | Date: 20/04/2018

Population composition is the description of apopulation according to characteristics such as age and sex. These data are often compared over time using population pyramid.

• ## Question: What are the different hormones?

Posted in: Biology | Date: 20/04/2018

Endocrine gland Hormone Main tissues acted on by hormone Posterior pituitary Oxytocin Uterus, milk ducts of breasts Thyroid gland Thyroxine (T4) Most tissues Tri-iodothyronine (T3) Most tissues Parathyroid glands Parathyroid hormone (PTH) Kidney, Bone cells

• ## Question: What is good about nuclear power?

Posted in: Chemistry | Date: 20/04/2018

The generation of electricity through nuclear energy reduces the amount of energy generated from fossil fuels (coal and oil). Less use of fossil fuels means lowering greenhouse gas emissions (CO2 and others). ... Another advantage is the required amount of fuel: less fuel offers more energy.

• ## Question: What are the advantages and disadvantages of nuclear power?

Posted in: Chemistry | Date: 20/04/2018

• Nuclear energy is a clean energy source in terms of carbon emissions released.
• Nuclear energy is a reliable source of power because the nuclear reactors used today have a pretty long life (they work for decades).
• Nuclear energy is a very powerful source of power which is also efficient (nuclear power has the highest energy density known by man).
• A nuclear power plant generates huge amount of clean electricity in a pretty small space.

• Nuclear power produces nuclear waste that is very hazardous for the environment and for any living being.
• Nuclear power is not a renewable energy source because uranium, plutonium and thorium are finite resources.
• Disposing nuclear waste is a very expensive activity that requires both high expenses and heavy military guard for the objective.
• Nuclear power has already produced several radioactive disasters that affected both human life and the environment.

• ## Question: What are the advantages and disadvantages of using nuclear power?

Posted in: Chemistry | Date: 20/04/2018

• Nuclear energy is a clean energy source in terms of carbon emissions released.
• Nuclear energy is a reliable source of power because the nuclear reactors used today have a pretty long life (they work for decades).
• Nuclear energy is a very powerful source of power which is also efficient (nuclear power has the highest energy density known by man).
• A nuclear power plant generates huge amount of clean electricity in a pretty small space.

• Nuclear power produces nuclear waste that is very hazardous for the environment and for any living being.
• Nuclear power is not a renewable energy source because uranium, plutonium and thorium are finite resources.
• Disposing nuclear waste is a very expensive activity that requires both high expenses and heavy military guard for the objective.
• Nuclear power has already produced several radioactive disasters that affected both human life and the environment.

• ## Question: What are the good things about nuclear power?

Posted in: Chemistry | Date: 20/04/2018

• Nuclear energy is a clean energy source in terms of carbon emissions released.
• Nuclear energy is a reliable source of power because the nuclear reactors used today have a pretty long life (they work for decades).
• Nuclear energy is a very powerful source of power which is also efficient (nuclear power has the highest energy density known by man).
• A nuclear power plant generates huge amount of clean electricity in a pretty small space.

• ## Question: What is the formula of centripetal acceleration?

Posted in: Physics | Date: 20/04/2018

The centripetal('center-seeking') acceleration is the motion inwards towards the center of a circle. The acceleration is equal to the square of the velocity, divided by the radius of the circular path.

• ## Question: What does it mean if the cross product of two vectors is 0?

Posted in: Physics | Date: 20/04/2018

he only way the dot product can be zero is if the angle between the two vectors is 90 degrees (or trivially if one or both of the vectors is the zero vector). Thus, two non-zero vectors have dot product zero if and only if they are orthogonal.

• ## Question: What are the benefits of using biodiesel?

Posted in: Chemistry | Date: 20/04/2018

Biodiesel is a domestically produced, clean-burning, renewable substitute for petroleum diesel. Using biodiesel as a vehicle fuel increases energy security, improves air quality and the environment, and provides safety benefits.

• ## Question: What is an example of a biofuel?

Posted in: Chemistry | Date: 20/04/2018

Examples of biofuels include ethanol (often made from corn in the United States and sugarcane in Brazil), biodiesel (vegetable oils and liquid animal fats), green diesel (derived from algae and other plant sources) and biogas (methane derived from animal manure and other digested organic material).

• ## Question: What is remolding?

Posted in: Biology | Date: 20/04/2018

The power to change aspects of living or inanimate things in order to increase efficiency. This power grants the user the ability to recreate people or things to improve their effectiveness. They are able to turn an item into an living being with vast superhuman powers or vice versa.

• ## Question: What is antagonastic?

Posted in: Biology | Date: 20/04/2018

In phytopathology, antagonism refers to the action of any organism that suppress or interfere the normal growth and activity of a plant pathogen, such as the main parts of bacteria or fungi. These organisms can be used for pest control and are referred to as Biological Control Agents´´. They may be predators, parasites,

Posted in: Chemistry | Date: 20/04/2018

1. Cost Benefit: As of now, biofuels cost the same in the market as gasoline does. However, the overall cost benefit of using them is much higher. They are cleaner fuels, which means they produce fewer emissions on burning. Biofuels are adaptable to current engine designs and perform very well in most conditions. This keeps the engine running for longer, requires less maintenance and brings down overall pollution check costs. With the increased demand of biofuels, they have a potential of becoming cheaper in future as well. So, the use of biofuels will be less of a drain on the wallet.

2. Easy To Source: Gasoline is refined from crude oil, which happens to be a non-renewable resource. Although current reservoirs of gas will sustain for many years, they will end sometime in near future. Biofuels are made from many different sources such as manure, waste from crops and plants grown specifically for the fuel.

3. Renewable: Most of the fossil fuels will expire and end up in smoke one day. Since most of the sources like manure, corn, switchgrass, soyabeans, waste from crops and plants are renewable and are not likely to run out any time soon, making the use of biofuels efficient in nature. These crops can be replanted again and again.

4. Reduce Greenhouse Gases: Fossil fuels, when burnt, produce large amount of greenhouse gases i.e. carbon dioxide in the atmosphere. These greenhouse gases trap sunlight and cause planet to warm. The burning of coal and oil increases the temperature and causes global warming. To reduce the impact of greenhouse gases, people around the world are using biofuels. Studies suggests that biofuels reduces greenhouse gases up to 65 percent.

5. Economic Security: Not every country has large reserves of crude oil. For them, having to import the oil puts a huge dent in the economy. If more people start shifting towards biofuels, a country can reduce its dependance on fossil fuels. More jobs will be created with a growing biofuel industry, which will keep our economy secure.

6. Reduce Dependance on Foreign Oil: While locally grown crops has reduce the nation’s dependance on fossil fuels, many experts believe that it will take a long time to solve our energy needs. As prices of crude oil is touching sky high, we need some more alternative energy solutions to reduce our dependance on fossil fuels.

7. Lower Levels of Pollution: Since biofuels can be made from renewable resources, they cause less pollution to the planet. However, that is not the only reason why the use of biofuels is being encouraged. They release lower levels of carbon dioxide and other emissions when burnt. Although the production of biofuels creates carbon dioxide as a byproduct, it is frequently used to grow the plants that will be converted into the fuel. This allows it to become something close to a self sustaining system.

1. High Cost of Production: Even with all the benefits associated with biofuels, they are quite expensive to produce in the current market. As of now, the interest and capital investment being put into biofuel production is fairly low but it can match demand. If the demand increases, then increasing the supply will be a long term operation, which will be quite expensive. Such a disadvantage is still preventing the use of biofuels from becoming more popular.

2. Monoculture: Monoculture refers to practice of producing same crops year after year, rather than producing various crops through a farmer’s fields over time. While, this might be economically attractive for farmers but growing same crop every year may deprive the soil of nutrients that are put back into the soil through crop rotation.

3. Use of Fertilizers: Biofuels are produced from crops and these crops need fertilizers to grow better. The downside of using fertilizers is that they can have harmful effects on surrounding environment and may cause water pollution. Fertilizers contain nitrogen and phosphorus. They can be washed away from soil to nearby lake, river or pond.

4. Shortage of Food: Biofuels are extracted from plants and crops that have high levels of sugar in them. However, most of these crops are also used as food crops. Even though waste material from plants can be used as raw material, the requirement for such food crops will still exist. It will take up agricultural space from other crops, which can create a number of problems. Even if it does not cause an acute shortage of food, it will definitely put pressure on the current growth of crops. One major worry being faced by people is that the growing use of biofuels may just mean a rise in food prices as well.

• ## Question: What is excretophore?

Posted in: Biology | Date: 20/04/2018

excretophore: A cell which serves to carry excreted matter away from the body.

• ## Question: What is a non zero magnitude?

Posted in: Physics | Date: 20/04/2018

That means that a vector can only have zero magnitude if all of its components arezero. ... Therefore any non-zero component has a nonzero square. The square of any number is at least 0. So the sum of squares when one component is nonzero is greater than zero.

• ## Question: What is the uppermost layer of the atmosphere?

Posted in: Geography | Date: 20/04/2018

uppermost layer of atmosphere is Exosphere.

• ## Question: Which layer of the atmosphere has the most air?

Posted in: Geography | Date: 20/04/2018

Tropospherehas the most air.

• ## Question: What is 1 atmospheric pressure?

Posted in: Geography | Date: 20/04/2018

One atmosphere (101 kPa or 14.7 psi) is also the pressure caused by the weight of a column of fresh water of approximately 10.3 m (33.8 ft). Thus, a diver 10.3 m underwater experiences a pressure of about 2 atmospheres (1 atm of air plus 1 atm of water).

• ## Question: What are the physical properties of a base?

Posted in: Chemistry | Date: 20/04/2018

PHYSICAL PROPERTIES OF BASE

• They have a bitter taste.
• They have slippery touch.
• They conduct electrically.
• It turns red litmus to blue.
• It turns colorless phenolphthalein to pink.

• ## Question: What are four characteristics of a base?

Posted in: Chemistry | Date: 20/04/2018

CHARACTERISTIC OF BASE

• They have a bitter taste.
• They have slippery touch.
• They conduct electrically.
• It turns red litmus to blue.
• It turns colorless phenolphthalein to pink.

• ## Question: What is the definition of plant physiology?

Posted in: Biology | Date: 20/04/2018

Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (biochemistry of plants), cell biology, genetics, biophysics and molecular biology.

• ## Question: What are four properties of acids of bases?

Posted in: Chemistry | Date: 20/04/2018

Properties of acids

• They are liquids.
• They are solutions of compounds in water.
• If concentrated they can be corrosive.
• Acids taste sour (for example, vinegar).
• Turn blue litmus paper red - this is an easy test for an acid!
• Usually react with metals to form salts.
• Acids contain hydrogen ions.

• ## Question: What does waste treatment mean?

Posted in: Biology | Date: 20/04/2018

Waste treatment refers to the activities required to ensure that waste has the least practicable impact on the environment. In many countries various forms of waste treatment are required by law.

• ## Question: How can we reduce waste?

Posted in: Biology | Date: 20/04/2018

Below, 9 simple changes you can make to reduce waste in your home.

Get to know the rules of recycling. Ditch the plastic bags Make a meal plan. Start relying on reusable containers. Start composting. Learn to repair rather than discard. Cancel unnecessary mail. Stop using disposable plates.

• ## Question: What are the major sources of waste?

Posted in: Biology | Date: 20/04/2018

Residences and homes where people live are some of the major sources of solidwaste. Garbage from these places include food wastes, plastics, paper, glass, leather, cardboard, metals, yard wastes, ashes and special wastes like bulky household items like electronics, tires, batteries, old mattresses and used oil.

• Liquid type: Waste can come in non-solid form. ...
• Solid type: Solid waste predominantly, is any garbage, refuse or rubbish that we make in our homes and other places. ...
• Hazardous type: ...
• Organic type: ...
• Recyclable type

• ## Question: What is the meaning of photonic?

Posted in: Physics | Date: 20/04/2018

Photonics is an area of study that involves the use of radiant energy (such as light), whose fundamental element is the photon. Photonic applications use the photon in the same way that electronic applications use the electron. Devices that run on light have a number of advantages over those that use electricity.

• ## Question: How does a convex lens work?

Posted in: Physics | Date: 20/04/2018

Convex lenses. ... Photo: A convex lens makes light rays converge (come together) at the focal point or focus. The distance from the center of the lens to the focal point is the focal length of the lens. Convex lenses are used in things like telescopes and binoculars to bring distant light rays to a focus in your eyes.

• ## Question: What is an example of a convex lens?

Posted in: Physics | Date: 20/04/2018

Convex lenses are used in things like telescopes and binoculars to bring distant light rays to a focus in your eyes

• ## Question: When was the first lens created?

Posted in: Physics | Date: 20/04/2018

Between the 11th and 13th century "reading stones" were invented. Often used by monks to assist in illuminating manuscripts, these were primitive plano-convex lenses initially made by cutting a glass sphere in half.

• ## Question: What is the most important river in Russia?

Posted in: Geography | Date: 20/04/2018

ural river is the most important river.

• ## Question: What are the uses of a lake?

Posted in: Geography | Date: 20/04/2018

The Great Lakes give us important benefits, such as providing water and food for human use, pollination and water purification to support ecosystems, and recreational opportunities and aesthetic benefits for humans to enjoy. Together, scientists call these ecosystem services

• ## Question: Which instrument is used to view distant objects?

Posted in: Physics | Date: 20/04/2018

Telescope is used toview distance objects.

• ## Question: What is the kinematics?

Posted in: Chemistry | Date: 20/04/2018

Kinematics is a branch of classical mechanics that describes the motion of points, bodies (objects), and systems of bodies (groups of objects) without considering the mass of each or the forces that caused the motion

• ## Question: What is the kinematics in animation?

Posted in: Chemistry | Date: 20/04/2018

Inverse kinematics (IK) is a method of animating that reverses the direction of the chain manipulation. ... The upper and lower arms are rotated by the IK solution which moves the pivot point of the wrist, called an end effector, toward the goal.

• ## Question: What is the point of incidence?

Posted in: Physics | Date: 20/04/2018

In geometric optics, the angle of incidence is theangle between a ray incident on a surface and the line perpendicular to the surface at the point of incidence, called the normal.

• ## Question: What is kinetic in physics?

Posted in: Chemistry | Date: 20/04/2018

In physics and engineering, kinetics is the branch of classical mechanics that is concerned with the relationship between motion and its causes, specifically, forces and torques.

• ## Question: What does optics mean in science?

Posted in: Physics | Date: 20/04/2018

the scientific study of sight and the behaviour of light, or the properties of transmission and deflection of other forms of radiation.

• ## Question: What is the interference theory?

Posted in: Physics | Date: 20/04/2018

Interference theory is a theory regarding human memory. Interference occurs in learning when there is an interaction between the new material and transfer effects of past learned behavior, memories or thoughts that have a negative influence in comprehending the new material.

• ## Question: What is the meaning of ray optics?

Posted in: Physics | Date: 20/04/2018

The ray in geometric optics is an abstraction useful for approximating the paths along which light propagates under certain circumstances. The simplifying assumptions ofgeometrical optics include that light rays: propagate in straight-line paths as they travel in a homogeneous medium.

• ## Question: What is interference in optics?

Posted in: Physics | Date: 20/04/2018

In physics, interference is a phenomenon in which two waves superpose to form a resultant wave of greater, lower, or the same amplitude. ... Interference effects can be observed with all types of waves, for example, light, radio, acoustic, surface water waves or matter waves.

• ## Question: What is the meaning of thermodynamics in chemistry?

Posted in: Chemistry | Date: 20/04/2018

Chemical thermodynamics is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics.

• ## Question: What kind of landform is the Hindu Kush?

Posted in: Geography | Date: 20/04/2018

Since the Hindu Kush separates one major climate zone of Asia from another, the range's climateshows great variations. The mountains of Swat Kohistan are within the area of the rain-bearing summer monsoon winds, and most of the eastern Hindu Kush

• ## Question: What is an atomic collision?

Posted in: Chemistry | Date: 20/04/2018

When a surface is bombarded with a beam of high-energy primary ions, atomic collisions between the beam and the solid cause the ejection of secondary ions, which can be characterized using a mass spectrometer. These secondary ions provide information on the atomic and molecular species present at the surface

• ## Question: What is bigger an electron or a quark?

Posted in: Chemistry | Date: 20/04/2018

we can't say what the size of a quark or electronactually is, we can safely say that if quarks have size at all, they are smaller than one ten-thousandth the size of a proton

• ## Question: What is the difference between real and ideal gas?

Posted in: Physics | Date: 20/04/2018

Ideal Gas: 1.It24 obeys ideal gas equation pV = µRT at all temperatures and pressures. 2.The volume of the molecules of an ideal gas is zero. 3.There is no intermolecular force between the molecules. 4.There is no intermolecular potential energy (U) because intermolecular force (F) is zero. 5.It12 has only kinetic energy. 6.At10 absolute zero, the volume pressure and internal energy become zero. Real Gas: 1.It24 does not obey pV = µRT at all values of temperature and pressure. 2.The volume of the molecules of a real gas is non-zero. 3.There is intermolecular force of attraction or repulsion depending on whether intermolecular separation is larger or small. Potential energy (U) does not equal to zero as intermolecular force (F) is not zero. 4.It13 has both kinetic and potential energy. 5.All real gases get liquified before reaching absolute zero. The internal energy of the liquefied gas is not zero.

• ## Question: What is Valency and example?

Posted in: Chemistry | Date: 20/04/2018

The valency of an element is the number of hydrogen atoms that can combine with or replace (either directly or indirectly) one atom of the element. ... For example, oxygen has six valence electrons, but its valency is 2. Some elements may have more than one combining power (or valency), while others have just one.

• ## Question: What is string theory in simple terms?

Posted in: Chemistry | Date: 20/04/2018

a cosmological theory based on the existence of cosmic strings.

• ## Question: What are the six states of matter?

Posted in: Physics | Date: 20/04/2018

There are three forms of matter: solids, liquids and gases. But that's not even half right. There are at least six: solids, liquids, gases, plasmas, Bose-Einstein condensates, and a new form of matter called "fermionic condensates"

• ## Question: What is the Valency of lithium?

Posted in: Chemistry | Date: 20/04/2018

It is +1.

• ## Question: What are the basic assumptions of kinetic theory of gases?

Posted in: Physics | Date: 20/04/2018

The simplest kinetic model is based on the assumptions that: (1) the gas is composed of a large number of identical molecules moving in random directions, separated by distances that are large compared with their size; (2) the molecules undergo perfectly elasticcollisions (no energy loss) with each other

• ## Question: What is the kinetic theory of ideal gases?

Posted in: Physics | Date: 20/04/2018

The kinetic theory of gases (also known as kinetic-molecular theory) explains the behavior of a hypothetical ideal gas. According to this theory,gases are made up of tiny particles in random, straight line motion. They move rapidly and continuously and make collisions with each other and the walls.

• ## Question: How do you find the Valency of an element?

Posted in: Chemistry | Date: 20/04/2018

The number of electrons within the outer shell of the element determine its valency. To calculate the valency of an element(or molecule, for that matter), there are multiple methods. ... The valency of an atom is equal to the number of electrons in the outer shell if that number is four or less.

• ## Question: What is the kinetic theory of heat?

Posted in: Physics | Date: 20/04/2018

The amount of kinetic energy in a substance is related to its phase. Gases have more kinetic energy than liquids. Liquids have more kinetic energy than solids. When a substance increases in temperature, heat is being added, and its particles are gaining kinetic energy.

• ## Question: What do we mean by Valency of an element?

Posted in: Chemistry | Date: 20/04/2018

In chemistry, the valence or valency of an element is a measure of its combining power with other atoms when it forms chemical compounds or molecules

• ## Question: How do we measure gas pressure?

Posted in: Physics | Date: 20/04/2018

Gas Pressure is measured in mmHg (millimeters of mercury) with a barometer, which gives the barometricpressure. The standard atmospheric pressure is "thepressure exerted by a mercury column of exactly 760 mm in height when the density of mercury= 13.5951 g/cm3 (0 degrees C) and the acceleration due to gravity."

• ## Question: What are the real gas?

Posted in: Physics | Date: 20/04/2018

Real gases are non-hypothetical gases whose molecules occupy space and have interactions; consequently, they adhere to gas laws.

Real gases can deviate from ideal behaviour, especially at high pressures and low temperatures. The extent of deviation is measured using the compressibility factor. The compressibility factor is obtained by solving for n in the ideal gas law: dividing the product of pressure and volume by the product of the gas constant

• ## Question: What are the four assumptions of the kinetic theory?

Posted in: Physics | Date: 20/04/2018

Assumptions :

(1)  All gases consists of molecules. The molecules of a gas are all alike and differ from those of other    gases. That is a gas will have same group of atoms.

(2)  The molecules of a gas are very small in size as compared to distance between then.

(3)  The molecules of a gas behave as perfect elastic spheres

(4)  The molecules are always in random motion and obey Newton’s law of motion. They have velocities    in all direction ranging from zero to infinity.

(5)  During their random motion, they collide against one another and the walls of the containing vessel .  The collisions of the molecules with one another and with the walls of vessel are perfectly elastic i.e. conserve momentum and (we assume) kinetic energy.

(6)  The collisions are almost instantaneous is time during which a collision takes place is negligible as compared to the time taken by the molecule to cover the free path.* [*Between two collisions, a molecule moves along a straight line and the distance covered between two successive collisions is called the freepath.

• ## Question: What are the three main points of the kinetic theory of gases?

Posted in: Physics | Date: 20/04/2018

Postulates of Kinetic Theory of Gases

The following assumptions are made in developing Kinetic theory of gases. We will show that the Kinetic theory of gases developed with these assumptions explain the macroscopic properties of the materials.

All gases consist of some basic units called molecules. The molecules are made up of single or group of atoms depending on the chemical nature of the gas.              The molecules move in random direction with random speed.              The molecules undergo collisions among themselves and to the walls of the container. These collisions are perfectly elastic. The collision time is very small compared to the average time spent by a molecule between two collisions.                   The size of the molecule is very small compared to the average intermolecular distance. Molecules do not exert any force among themselves or to the walls except during collision.                   The molecules obey Newton's Law of Motion.                         The number of gas molecules is so large that at every position of infinitesimal volume of the container, the density and distribution of different physical parameters are same. The above parameters are also independent of direction and time at a steady state.

• ## Question: What are the postulates of the kinetic theory of gases?

Posted in: Physics | Date: 20/04/2018

Postulates of Kinetic Theory of Gases

The following assumptions are made in developing Kinetic theory of gases. We will show that the Kinetic theory of gases developed with these assumptions explain the macroscopic properties of the materials.

All gases consist of some basic units called molecules. The molecules are made up of single or group of atoms depending on the chemical nature of the gas.              The molecules move in random direction with random speed.              The molecules undergo collisions among themselves and to the walls of the container. These collisions are perfectly elastic. The collision time is very small compared to the average time spent by a molecule between two collisions.                   The size of the molecule is very small compared to the average intermolecular distance. Molecules do not exert any force among themselves or to the walls except during collision.                   The molecules obey Newton's Law of Motion.                         The number of gas molecules is so large that at every position of infinitesimal volume of the container, the density and distribution of different physical parameters are same. The above parameters are also independent of direction and time at a steady state.

• ## Question: What is the state of kinetic theory?

Posted in: Physics | Date: 20/04/2018

The Kinetic Theory of Matter states that matter is composed of a large number of small particles—individual atoms or molecules—that are in constant motion. This theory is also called the Kinetic-Molecular Theory of Matter and the Kinetic Theory of Gases.

• ## Question: What is the kinetic theory of heat?

Posted in: Physics | Date: 20/04/2018

(1)  All gases consists of molecules. The molecules of a gas are all alike and differ from those of other    gases. That is a gas will have same group of atoms.

(2)  The molecules of a gas are very small in size as compared to distance between then.

(3)  The molecules of a gas behave as perfect elastic spheres

(4)  The molecules are always in random motion and obey Newton’s law of motion. They have velocities    in all direction ranging from zero to infinity.

(5)  During their random motion, they collide against one another and the walls of the containing vessel .  The collisions of the molecules with one another and with the walls of vessel are perfectly elastic i.e. conserve momentum and (we assume) kinetic energy.

(6)  The collisions are almost instantaneous is time during which a collision takes place is negligible as compared to the time taken by the molecule to cover the free path.* [*Between two collisions, a molecule moves along a straight line and the distance covered between two successive collisions is called the freepath.

(7)  No appreciable forces act on the molecules except during a collision. To the extent that this is true a molecule moves with uniform velocity between collisions. Because we have assumed the molecules  to be small, the average distance between the molecules is large compared to the size of a molecules. Hence, we assume that the range of molecular forces is comparable to the molecular size.Facebook

• ## Question: What is reproductive oppression?

Posted in: Biology | Date: 20/04/2018

the control and exploitation. of women, girls, and individuals through our bodies, sexuality, labor, and reproduction—rather than a narrow. focus on protecting the legal right to abortion, SisterSong

• ## Question: What is the definition of reproductive health?

Posted in: Biology | Date: 20/04/2018

Reproductive health refers to the diseases, disorders and conditions that affect the functioning of the male and female reproductive systems during all stages of life.

• ## Question: What are the reproductive disorders?

Posted in: Biology | Date: 20/04/2018

Reproductive disorders are diseases involving the reproductive system, includingreproductive tract infections, congenital abnormalities, cancers of the reproductivesystem and sexual dysfunction.

• ## Question: What is the cause of infertility in female?

Posted in: Biology | Date: 20/04/2018

Five causes of female infertility

Ageing. A woman's age is the most significant factor influencing her fertility. ... Polycystic ovarian syndrome (PCOS) PCOS is a hormone imbalance which results in disrupted menstrual and ovulation cycles. ... Endometriosis. ... Weight. ... Sexually transmitted infections (STIs)

• ## Question: What is the audible frequency range for the human beings?

Posted in: Physics | Date: 21/04/2018

audible frequency range is 20Hz to 20 kHz

• ## Question: Is baking powder an acid or a base?

Posted in: Chemistry | Date: 21/04/2018

Baking powder is basic in nature as when it is tested with litmus paper it turns blue.

• ## Question: Is sugar and ionic compound?

Posted in: Chemistry | Date: 21/04/2018

sugar is a covalent compound and donot form any ions in the aqueous solution.

• ## Question: What is smaller than an atom quark?

Posted in: Chemistry | Date: 21/04/2018

quark i smallest particle known. protons are made up of quarks. if there is any size of quark defined,then quark would be the smallest particle.

• ## Question: What is meant by Covalency?

Posted in: Chemistry | Date: 21/04/2018

valency is defined as the cahracteristaion of valence by sharing of electrons in a compound that the number of electron an atom can share.

• ## Question: Why do you use a resistor with an LED?

Posted in: Physics | Date: 21/04/2018

Resistore is used to limit the current to a safe valye and prevent from it burns.

• ## Question: How many lattice points are there in one unit cell of Body-centred?

Posted in: Biology | Date: 21/04/2018

in BCC, there are 9 lattice point i. e. 8 at cormers and 1 at centres.

• ## Question: Can you have a negative magnitude of acceleration?

Posted in: Physics | Date: 21/04/2018

magnitude of acceleration is always positive. negative of any value only shows it direction.

• ## Question: Can distance traveled ever be less than the magnitude of the displacement?

Posted in: Physics | Date: 21/04/2018

No distance can never be less than dispacement.it can only be equal or greater than magnitude of dispacement.

• ## Question: What is the instrument used to magnify objects?

Posted in: Physics | Date: 21/04/2018

microscope is used for magnifying objects.

• ## Question: What is the value of R in PV NRT?

Posted in: Physics | Date: 21/04/2018

value of R is 8.314 j/mol. K

• ## Question: What is a example of a liquid?

Posted in: Physics | Date: 21/04/2018

liquide having volume and taking shape of its container. for ex. milk, water etc

• ## Question: What holds together the particles in a solid?

Posted in: Chemistry | Date: 21/04/2018

the force whicj binds together in solid is called vanderwalls force.

• ## Question: How do we measure gas pressure?

Posted in: Physics | Date: 21/04/2018

Barometer is used to measure the gas pressure. Barometer works on the principle of liquid pressure of mercury.

• ## Question: What happens when you put a gas under high pressure?

Posted in: Physics | Date: 21/04/2018

when it happens so, liquification starts due to compression and it changes into liquid.

• ## Question: What is inside of an atom?

Posted in: Chemistry | Date: 21/04/2018

atims consist of proton and neutron inside it and eleectron revolve outside.

• ## Question: How does temperature affect the pressure of a gas?

Posted in: Physics | Date: 21/04/2018

temperature of gas is directly proportional to its pressure.

• ## Question: Are lemons alkaline?

Posted in: Chemistry | Date: 21/04/2018

initially lemon juice is citric acid and hence acid in nature. but after entering into body it becomes alkaline in nature after metabolism.

• ## Question: What is the main cause of friction?

Posted in: Physics | Date: 16/05/2018

Consider a particle which has mass ‘m’ and is moving with a uniform velocity.

this particle is moving along a certain surface of ROUGH texture. so now, when the lower surface of the particle comes in contact with the upper surface of the floor / ground, the particle loses some of its velocity because the roughness of the surface stops it from going ahead. since to overcome this force of opposition, the particle spends some of its energy. and this produces heat.

hence, friction is defined as, ‘the resistance that one surface or object encounters when moving over another.’

• ## Question: What are the four different types of friction?

Posted in: Physics | Date: 16/05/2018

There are four types of friction: static, sliding, rolling, and fluid friction. Static, sliding, and rolling friction occur between solid surfaces. Static friction is strongest, followed by sliding friction, and then rolling friction, which is weakest. Fluid friction occurs in fluids, which are liquids or gases

• ## Question: What is a balanced force?

Posted in: Physics | Date: 16/05/2018

Balance forces are two forces acting in opposite directions on an object, and equal in size. Anytime there is a balanced force on an object, the object stays still or continues moving continues to move at the same speed and in the same direction

• ## Question: What is a doab?

Posted in: Social Studies,Geography | Date: 16/05/2018

Doab (from dō, "two" + āb, "water" or "river") is a term used in India and Pakistan for the "tongue," or water-rich tract of land lying between two converging, or confluent, rivers. It is similar to an interfluve.

• ## Question: What are the disadvantages of friction?

Posted in: Physics | Date: 16/05/2018

Despite the fact that the friction is very important in our daily life, it also has some disadvantages like:

1. The main disadvantage of friction is that it produces heat in various parts of machines. In this way     some useful energy is wasted as heat energy.

2. Due to friction we have to exert more power in machines.

3. It opposes the motion.

4. Due to friction, noise is also produced in machines.

5. Due to friction, engines of automobiles consume more fuel which is a money loss.

6. Machine efficency is decreased: energy input is lost to heat

7. Getting shocked by doorknobs

8. Rug burn

9. It counteracts movement and so it takes more energy to move, it can cause unwanted heat (e.g. in machine parts), and it wears things out like shoes.

10. Forest fires are caused due to friction between branches of trees

• ## Question: What is the Ka of benzoic acid?

Posted in: Chemistry | Date: 16/05/2018

The acid dissociation constant (Ka) for benzoic acid is 6.3 x 10^-5. ..

• ## Question: What are the laws of motion?

Posted in: Physics | Date: 16/05/2018

First law: In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.[2][3]

Second law: In an inertial reference frame, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma. (It is assumed here that the mass m is constant – see below.)

Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.

• ## Question: What is an example of curvilinear motion?

Posted in: Physics | Date: 16/05/2018

A stone thrown into the air at an angle. Curvilinear motion describes the motion of a moving particle that conforms to a known or fixed curve.

• ## Question: What is the definition of curvilinear motion?

Posted in: Physics | Date: 16/05/2018

The motion of an object moving in a curved path is called curvilinear motion. Example: A stone thrown into the air at an angle. Curvilinear motion describes the motion of a moving particle that conforms to a known or fixed curve.

• ## Question: What is the cause of motion?

Posted in: Physics | Date: 16/05/2018

Force vectors.

F=ma

If you have a mass, you have to give it a force in order to achieve acceleration, thereby gaining motion.

• ## Question: What are some examples of vibratory motion?

Posted in: Physics | Date: 16/05/2018

A tuning fork set to vibrate is a classical example for this. Vibration of phone! Vibration of skin of drum when beaten.

• ## Question: What are the two main types of friction?

Posted in: Physics | Date: 16/05/2018

There are two main types of friction, static friction and kinetic friction. Static friction operates between two surfaces that aren't moving relative to each other, while kinetic friction acts between objects in motion.

• ## Question: How do we describe motion?

Posted in: Physics | Date: 16/05/2018

“A body is said to be in motion,if it changes its position with respect to its surroundings.”

Surroundings are the places in its neighborhood where various objects are present.The state of rest or motion of a body is relative.For example,a passenger sitting in a moving bus is at rest because he is not changing his position with respect to other passengers or objects in the bus.But to an observer outside the bus,the passengers and the objects inside the bus are in motion.Therefore we can defined rest as “A body is said to be at rest ,if it does not change its position with respect to its surroundings.”

• ## Question: What are the three examples of circular motion?

Posted in: Physics | Date: 16/05/2018

Rectilinear motion means motion along a straight line. This is a useful topic to study for learning how to describe the movement of cars along a straight road or of trains along straight railway tracks.

• ## Question: Which is more acidic water or alcohol?

Posted in: Chemistry | Date: 16/05/2018

Water is a better acid than alcohol because of the electron donating nature of the alkyl group attached to the oxygen which destabilizes the hydroxide(in the case of alcohol,Alkoxide) ion and makes it tougher for the oxygen to donate the proton.

• ## Question: Which one is more acidic phenol or water?

Posted in: Chemistry | Date: 16/05/2018

Phenol is more acidic than water because of losing an H+ ion, it forms a phenoxide ion which is stabilized by resonance, while if water loses H+, it forms hydroxide, which is not stabilized by resonance.

• ## Question: Why friction is a necessary?

Posted in: Physics | Date: 16/05/2018

If there is anything which moves forward with respect to something else while in contact with it without any external force acting it's because of god damn friction. ... Friction is evil: If there is external force available then the same friction slows it down.

• ## Question: Why formic acid is more acidic than acetic acid?

Posted in: Chemistry | Date: 16/05/2018

Formic acid has a pka of 3.75

Acetic acid has a pka of 4.75

Therefore formic acid is a stronger acid than acetic acid.

If you want to know why, you have to look at stabilizing and destabilizing factors of their conjugate bases. If the conjugate base is more stable, the compound it corresponds to is more acidic.

If we look at the conjugate base for formic acid (formate ion): its conjugate base is stabilized by resonance, induction, and electronegativity(a negative charge is more comfortable on an O because it's electronegative).

Now if we look at the conjugate base for acetic acid (acetate ion): its conjugate base is stabilized by resonance, induction, and electronegativity just like the formate ion. The only difference here is that there's a CH3 group instead of an H adjacent to the carbonyl. This methyl group is an electron donating group which can destabilize the negative charge of the conjugate base which is why acetic acid is less acidic than formic acid.

• ## Question: Are strong bases good nucleophiles?

Posted in: Chemistry | Date: 16/05/2018

that all of these nucleophiles will have faster SN2 reactions in polar aprotic solvents. ... Some good nucleophiles are strong bases, and some are weak bases. Base strength is measured by looking at the pKa of the conjugate acid.

• ## Question: How is friction calculated?

Posted in: Physics | Date: 16/05/2018

Calculate the force of friction using the formula:

F = μN

Where N is the normal force and μ is the friction coefficient for your materials and whether they’re stationary or moving. The normal force is equal to the weight of the object, so this can also be written:

F = μmg

Where m is the mass of the object and g is the acceleration due to gravity. The friction acts to oppose the motion of the object.

• ## Question: Is Hydrosulfuric acid a strong acid?

Posted in: Chemistry | Date: 16/05/2018

A strong acid is one that completely ionizes (dissociates) in a solution (provided there is sufficient solvent). ... Examples of strong acids are hydrochloric acid (HCl), hydroiodic acid (HI), hydrobromic acid (HBr), perchloric acid (HClO4), nitric acid (HNO3) and sulfuric acid (H2SO4).

• ## Question: What form of glycine is used in the human body?

Posted in: Chemistry | Date: 16/05/2018

.the form of glycine used by the human body is d-glycine

• ## Question: why relative density have no units?

Posted in: Physics | Date: 16/05/2018

Density has a unit but relative density does not have any unit. ... Relative density = Density of the substance/Density of water at 4°C. As both the numerator and the denominator on the RHS of the above formula has the same unit (i.e. kg/m3) they get cancelled. Hence relative density has no unit.

• ## Question: What is a ray of light?

Posted in: Physics | Date: 16/05/2018

A light ray is a line (straight or curved) that is perpendicular to the light's wavefronts; its tangent is collinear with the wave vector. Light rays in homogeneous media are straight. They bend at the interface between two dissimilar media and may be curved in a medium in which the refractive index changes.

• ## Question: What is meant by theoretical plate?

Posted in: Chemistry | Date: 16/05/2018

A theoretical plate in many separation processes is a hypothetical zone or stage in which two phases, such as the liquid and vapor phases of a substance, establish an equilibrium with each other. Such equilibrium stages may also be referred to as an equilibrium stage, ideal stage, or a theoretical tray.

• ## Question: What is the difference music and noise?

Posted in: Physics | Date: 16/05/2018

Musical sounds are periodic and somewhat regular. They are pleasing to our ears and minds, and sound has been one of the greatest forms of expression since the beginning of time. Unpleasant sound is often described as noise. Noise is more irregular.

• ## Question: Which is more acidic phenol or alcohol?

Posted in: Chemistry | Date: 16/05/2018

Both alcohols and phenols are weak acid the alcohols are less acidic than phenols because it is very tough to remove the H ion easily because phenoxide ion formed is stablised to some extent This is the negative charge on the oxygen atom around the ring . Alkyl group in alcohol don't have resonance.

• ## Question: What makes something more acidic?

Posted in: Chemistry | Date: 16/05/2018

When a hydrogen ion is released, the solution becomes acidic. When a hydroxide ion is released, the solution becomes basic. Those two special ions determine whether you are looking at an acid or a base.

• ## Question: Why is a thiol more acidic than alcohol?

Posted in: Chemistry | Date: 16/05/2018

Acidity is described as ability to loose H+ ion in solution. So in thiols(R-SH) after loosing H+ we have negative charge on sulfur which is more stabilized. So if the resulting state of compound is more stable, its activity to reach there is faster and hence thiols loose H+ ions easily as compared to alcohols for which negative charge on oxygen is unstable and will not let H+ go that easily.

• ## Question: What are the three main points of the kinetic theory of gases?

Posted in: Physics | Date: 16/05/2018

There are three main components to kinetic theory: *No energy is gained or lost when molecules collide. *The molecules in a gas take up a negligible (able to be ignored) amount of space in relation to the container they occupy.  *The molecules are in constant, linear motion.

• ## Question: What is the kinetic theory of a solid?

Posted in: Physics | Date: 16/05/2018

According to Kinetic Molecular Theory:

All objects are made up of tiny particles called atoms. These atoms are always moving (notwithstanding the third law of thermodynamics), so those atoms would have kinetic energy. We can observe this energy as the temperature of an object, but the true measure how how much kinetic energy a solid has is given by the expression $Q = m c \Delta t.$

• ## Question: What is the cause of gas pressure in a closed container?

Posted in: Physics | Date: 16/05/2018

The particles in a gas move quickly in all directions, but they don't get far before they bump into each other or the walls of their container. When gas particles hit the walls of their container they cause pressure. The more particles that hit the walls, the higher the pressure.

• ## Question: What are the effects of zero gravity on the human body?

Posted in: AMITE | Date: 16/05/2018

Bones demineralise, losing calcium and strength in space. In effect, osteoporosis sets in. Astronauts risk losing 2% of their bone mass for every month spent in zero gravity. To reduce muscle and bone loss, astronauts have to exercise for two or more hours every day.

• ## Question: What is fertilization?

Posted in: Biology | Date: 16/05/2018

the action or process of fertilizing an egg or a female animal or plant, involving the fusion of male and female gametes to form a zygote.

• ## Question: Who discovered the mirror?

Posted in: Physics | Date: 16/05/2018

Justus von Liebig

• ## Question: What is granite used for?

Posted in: Chemistry | Date: 16/05/2018

Granite is used in buildings, bridges, paving, monuments, and many other exterior projects. Indoors, polished granite slabs and tiles are used in countertops, tile floors, stair treads and many other design elements.

• ## Question: What are pure substances?

Posted in: Chemistry | Date: 16/05/2018

The pure substance within chemistry is a very simple concept to grasp. Pure substances are defined as substances that are made of only one type of atom or only one type of molecule (a group of atoms bonded together). The measure of whether a substance is pure is known as purity.

• ## Question: What is sound energy?

Posted in: Physics | Date: 16/05/2018

Sound energy is a form of energy that is associated with vibrations of matter. It is a type of mechanical wave which means it requires an object to travel through. This object includes air and water. Sound originates from the vibrations that result after an object applies a force to another object

• ## Question: What is deposition?

Posted in: Chemistry | Date: 16/05/2018

Deposition is the geological process in which sediments, soil and rocks are added to a landform or land mass. Wind, ice, water, and gravity transport previously weathered surface material, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of sedimen

• ## Question: What is a fundamental note?

Posted in: Physics | Date: 16/05/2018

Fundamental note is the note of the lowest frequency of the periodic waveform. Above the fundamental notes are called overtones.

• ## Question: Is acetic acid more acidic than benzoic acid?

Posted in: Chemistry | Date: 16/05/2018

The answer lies in the stability of the conjugate bases  formed by these two acids.

We only need to compare the point of difference among the two:

Benzoic acid : Ph-COO-

The phenyl ring has a minus I (inductive effect ) and also pulls the -ve charge density on oxygen atom through resonance. this leads to the formation of a stable conjugate base. so benzoic acid is quite acidic.

Acetic acid : CH3COO-

The methyl group has a plus I (inductive effect ) and pushes the electron cloud towards oxygen which already has a negative charge. This destabilizes the molecule and thus the acidity of the molecule and thus acetic acid is less acidic.

• ## Question: What is a positive displacement

Posted in: Physics | Date: 16/05/2018

A positive-displacement pump is one that displaces (delivers) the same amount of liquid for each rotating cycle of the pumping element. Constant delivery during each cycle is possible because of the close-tolerance fit between the pumping element and the pump case. That is, the amount of liquid that slips past the pumping element in a positive-displacement pump is minimal and negligible compared to the theoretical maximum possible delivery. The delivery per cycle remains almost constant, regardless of changes in pressure against which the pump is working. Note that if fluid slippage is substantial, the pump is not operating properly and should be repaired or replaced.

Example: Reciprocating pump, Screw pump, Piston pump

• ## Question: Who invented lenses for glasses?

Posted in: Physics | Date: 16/05/2018

According to some sources the invention of the first wearable pair of eyeglasses occurred in the 13th century in Italy. Salvino D'Armate probably invented eyeglasses in around 1285, though various sources suggest an earlier origin.

• ## Question: When was Optics discovered?

Posted in: Physics | Date: 16/05/2018

13th century He discovered that light reflects from objects rather than emanating from them. Between the 11th and 13th century "reading stones" were invented. Often used by monks to assist in illuminating manuscripts, these were primitive plano-convex lenses initially made by cutting a glass sphere in half.

• ## Question: What are the six strongest acids?

Posted in: Chemistry | Date: 16/05/2018

H2SO4. Sulfuric Acid. HCl. Hydrochloric Acid. HBr. Hydrobromic Acid. HI. Hydroiodic Acid. HNO3. Nitric Acid. HClO4. Perchloric Acid.

• ## Question: Why is cysteine so important?

Posted in: Chemistry | Date: 16/05/2018

Because it has a very reactive sulfhydryl group at its side chain. This puts cysteine in special position that cannot be replaced or substituted by any other amino acid. Because disulfide bridges formed by cysteine residues are permanent component of protein primary structure.

• ## Question: What is the Atkinson shiffrin model?

Posted in: Physics | Date: 16/05/2018

The Atkinson–Shiffrin model (also known as the multi-store model or modal model) is a model of memory proposed in 1968 by Richard Atkinson and Richard Shiffrin. ... a short-term store, also called working memory or short-term memory, which receives and holds input from both the sensory register and the long-term store, and.

• ## Question: Who discovered the lens?

Posted in: Physics | Date: 16/05/2018

Though contact lenses seem to be a recent phenomenon, the famous Italian architect, mathematician and inventor Leonardo da Vinci (1452-1519) produced the first known sketches (in 1508) that suggested the optics of the human eye could be altered by placing the cornea directly in contact with water.

• ## Question: Why is light a ray?

Posted in: Physics | Date: 16/05/2018

The ray that bounces off the surface at an angle is known as the reflected ray. Refracted rays are when the light goes through the surface, bending due to the change of material (or 'medium'). For example, if a ray of light travels from air into water, or into a block of glass, the light ray will bend as a result.

• ## Question: What is plasma?

Posted in: Physics | Date: 16/05/2018

Plasma is the fourth state of matter. The fourth is plasma. To put it very simply, a plasma is an ionized gas, a gas into which sufficient energy is provided to free electrons from atoms or molecules and to allow both species, ions and electrons, to coexist

• ## Question: What is meant Rf value?

Posted in: Chemistry | Date: 16/05/2018

RF value (in chromatography) The distance travelled by a given component divided by the distance travelled by the solvent front. For a given system at a known temperature, it is a characteristic of the component and can be used to identify components.

• ## Question: What is darkness made up of?

Posted in: Physics | Date: 16/05/2018

These possibilities are known as massive compact halo objects, or "MACHOs". But the most common view is that dark matter is not baryonic at all, but that it is made up of other, more exotic particles like axions or WIMPS (Weakly Interacting Massive Particles). Darkness is not up of any kind of matter. It's just absence of light. Just as how cold is the absence of heat.

• ## Question: Are eggs alkaline?

Posted in: Chemistry | Date: 16/05/2018

Acid-forming foods include most high-protein foods, such as meat, fish, eggs, and most legumes (beans and peas, except lentils, which are alkaline-forming). Sugar, coffee, alcohol, and most grains are also acid-forming.

• ## Question: What is first order and second order reaction?

Posted in: Chemistry | Date: 16/05/2018

First order

A first order reaction depends on the concentration of only one reactant (a unimolecular reaction). Other reactants can be present, but each will be zero order. The rate law for such a reaction is

{\displaystyle {\frac {-d[{\ce {A}}]}{dt}}=k[{\ce {A}}],} [{\displaystyle {\frac {-d[{\ce {A}}]}{dt}}=k[{\ce {A}}],}]

The half-life is independent of the starting concentration and is given by {\displaystyle t_{\frac {1}{2}}={\frac {\ln {(2)}}{k}}} [{\displaystyle t_{\frac {1}{2}}={\frac {\ln {(2)}}{k}}}] .

Examples of such reactions are:

{\displaystyle {\ce {H2O2 (l) -> {H2O (l)}+ 1/2O2 (g)}}} [{\displaystyle {\ce {H2O2 (l) -> {H2O (l)}+ 1/2O2 (g)}}}] {\displaystyle {\ce {SO2Cl2 (l) -> {SO2 (g)}+ Cl2 (g)}}} [{\displaystyle {\ce {SO2Cl2 (l) -> {SO2 (g)}+ Cl2 (g)}}}] {\displaystyle {\ce {2N2O5 (g) -> {4NO2 (g)}+ O2 (g)}}} [{\displaystyle {\ce {2N2O5 (g) -> {4NO2 (g)}+ O2 (g)}}}]

In organic chemistry, the class of SN1 (nucleophilic substitution unimolecular) reactions consists of first-order reactions. For example, in the reaction of aryldiazonium ions with nucleophiles in aqueous solution ArN2+ + X− → ArX + N2, the rate equation is r = k[ArN2+], where Ar indicates an aryl group

Second order

A reaction is said to be second order when the overall order is two. The rate of a second-order reaction may be proportional to one concentration squared {\displaystyle r=k[A]^{2}\,} [r=k[A]^{2}\,] , or (more commonly) to the product of two concentrations {\displaystyle r=k[A][B]\,} [r=k[A][B]\,] . As an example of the first type, the reaction NO2 + CO → NO + CO2 is second-order in the reactant NO2 and zero order in the reactant CO. The observed rate is given by {\displaystyle r=k[{{\ce {NO2}}}]^{2}\,} [{\displaystyle r=k[{\ce {NO2}}]^{2}\,}] , and is independent of the concentration of CO.[10]

For the single-component system, the time dependence of the concentration is given by

{\displaystyle {\ce {{\frac {1}{[A]}}= {\frac {1}{[A]0}}+ 2kt}}} [{\displaystyle {\ce {{\frac {1}{[A]}}= {\frac {1}{[A]0}}+ 2kt}}}]

The time dependence for two components with unequal concentrations is

{\displaystyle {\ce {{\frac {[A]}{[B]}}={\frac {[A]0}{[B]0}}{\mathit {e}}^{([A]0-[B]0){\mathit {kt}}}}}} [{\displaystyle {\ce {{\frac {[A]}{[B]}}={\frac {[A]0}{[B]0}}{\mathit {e}}^{([A]0-[B]0){\mathit {kt}}}}}}] ;

if the concentrations are equal, they satisfy the previous equation.

The second type includes nucleophillic addition-elimination reactions, such as the alkaline hydrolysis of ethyl acetate:[9]

CH3COOC2H5 + OH− → CH3COO− + C2H5OH

This reaction is first-order in each reactant and second-order overall: r = k[CH3COOC2H5][OH−]

If the same hydrolysis reaction is catalyzed by imidazole, the rate equation becomes[9] r = k[imidazole][CH3COOC2H5]. The rate is first-order in one reactant (ethyl acetate), and also first-order in imidazole which as a catalyst does not appear in the overall chemical equation.

Another well-known class of second-order reactions are the SN2 reactions, such as the reaction of n-butyl bromide with sodium iodide in acetone:

CH3CH2CH2CH2Br + NaI → CH3CH2CH2CH2I + NaBr↓

This same compound can be made to undergo an E2 reaction, another common type of second-order reaction, if the sodium iodide and acetone are replaced with sodium tert-butoxide as the salt and tert-butanol as the solvent:

CH3CH2CH2CH2Br + NaOt-Bu → CH3CH2CH=CH2 + NaBr + HOt-Bu

• ## Question: what was tithe

Posted in: Social Studies | Date: 16/05/2018

The first tithe is giving of one tenth of agricultural produce (after the giving of the standard terumah) to the Levite (or Aaronic priests). Historically, during the First Temple period, the first tithe was given to the Levites

• ## Question: How can friction be increased or decreased?

Posted in: Physics | Date: 16/05/2018

Creating a More Frictive Surface

Create a “rougher” or more adhesive point of contact. ...

Press the two surfaces together harder. ...

Stop any relative motion. ...

Remove lubrication between the two surfaces. ...

Remove wheels or bearings to create sliding friction. ...

Increase the fluid viscosity.

Reducing Friction. There are several ways to reduce friction: The use of bearing surfaces that are themselves sacrificial, such as low shear materials, of which lead/copper journal bearings are an example. Replace sliding friction with rolling element friction, such as with the use of rolling element bearings.

• ## Question: Where is the strongest gravity on Earth?

Posted in: AIEEE | Date: 16/05/2018

Earth's gravity is stronger at the poles than the equator for two reasons:

The centrifugal "force" cancels out the gravity minimally, more so at the equator than at the poles. The poles are closer to the center due to the equatorial bulge, and thus have a stronger gravitational field.

• ## Question: What is uniform and non uniform motion?

Posted in: Physics | Date: 16/05/2018

UNIFORM MOTION AND NON-UNIFORM MOTION: A body is said to be in uniform motion, if it travels equal distances in equal intervals of time.A body is said to have non-uniform motion, if it travels unequal distances in equal intervals of time. ... We can say that the motion is called uniform motion

• ## Question: What is moment of inertia formula?

Posted in: Physics | Date: 16/05/2018

The moment of inertia, otherwise known as the angular mass or rotational inertia, of a rigid body is a tensor that determines the torque needed for a desired angular acceleration about a rotational axis. For a point mass the moment of inertia is just the mass times the square of perpendicular distance to the rotation axis, I = mr2.

• ## Question: What is a semiconductor? Describe the two main types of semiconductors.

Posted in: Chemistry | Date: 16/05/2018

Semiconductors allow to flow a very small quantity of electric current through them at the room temperature. These are the solids with conductivities in the intermediate range from 10–6 to 104 ohm–1m–1.Semiconductors are perfect insulator atabsolute zero. Silicon and Germanium are examples of semiconductor.

There are two types of main semiconductors (i)    n–type semiconductor  (ii) p–type semiconductor  n–type semiconductor: there semiconductors have Electron – rich impurities. Silicon and germanium belong to group 14 of the periodic table and each has four valence electrons .

Four out of five electrons are used in the formation of four covalent bonds with the four neighbouring silicon atoms. Extra fifth electron is becomes delocalized. These delocalized electrons increase theconductivity of doped silicon or germanium both . Here the increase in conductivity is due to the negatively charged mobile electron.

Hence semiconductors doped with electron–rich impurity are called n–type semiconductor   p–type semiconductor:– Si or Ge can also be doped with a group 13 element. The elements of group 13 contains only three valence electrons. Elements of 14th group have has 4 valence electron.

The place where the fourth valence electron is missing is called electron hole .An electron from a neighbouring atom can come and fill the electron hole, but in doing so it would leave an electron hole at its original position. If it happens, it would appear as if the electron hole has moved in the direction opposite to that of the electronthat filled it.

Under the influence of electric field, electrons would move towards the positively charged plate through electronic holes, but it would appear as if electron holes are positively charged and are moving towards negatively charged plate. This type of semi conductors are called p–type semiconductors.

• ## Question: What is astigmatism explsin

Posted in: Physics | Date: 17/05/2018

Astigmatism is an imperfection in the curvature of your cornea — the clear, round dome covering the eye's iris and pupil — or in the shape of the eye's lens. Astigmatism is a type of refractive error in which the eye does not focus light evenly on the retina. This results in distorted or blurred vision at all distances.

• ## Question: Why do we need a capacitor in a circuit?

Posted in: Physics | Date: 17/05/2018

A capacitor can store electric energy when it is connected to its charging circuit. And when it is disconnected from its charging circuit, it can dissipate that stored energy, so it can be used like a temporary battery. ... In car audio systems, large capacitors store energy for the amplifier to use on demand. Purpose of a capacitor is to keep negative & positive charges separated from each other. The two different charges are held on two different plates which are separated by an insulator. presence of capacitor in an AC circuit changes the phase angle between voltage and current.

• ## Question: Why is ice at zero degree celsius more effective in cooling than water at zero d...

Posted in: Chemistry | Date: 17/05/2018

Ice is more effective in cooling than water at the same temperature because ice can absorb latent heat as well as the heat energy in order to attain room temperature. Water at 0 C can absorb heat energy only to attain the room temperature.

Because water has high specific heat capacity so its stores more heat and is unable to cool things very easily at zero degree celsius that is why we use ice because it has low specific heat which means that it stores less heat inside it. Because ice release the latent heat when it change from liquid to solid.

• ## Question: How do you increase or decrease friction?

Posted in: Physics | Date: 17/05/2018

Method of decreasing and increasing friction Method of decreasing friction: By polishing: Friction between two surfaces can be reduced by polishing them. The interlocking and projections are minimized by this method. Ball-bearing:  As the rolling friction less than the sliding friction consequently in rotating machinery, the shafts are fixed on the ball bearing so that the friction can be reduced considerably. For example-the free wheel of a cycle, the axle of a motorcar, the shafts of the motor dynmo etc. are provided with ball-bearing. Lubricants: Friction between two surfaces can be decreased by using lubricants. A lubricant is a substance (a solid or a liquid) which forms a thin layer between the two surfaces in contact. It also fills the depressions present in the surfaces of contact and reduces friction considerably. In light machinery thin oils with low viscosity are used, in heavy and fast moving machinery thick oils and solutes (grease) are used. Streamline: The friction due to air is reduced by making the automobiles streamline. Methods of increasing friction: By making the surface rough friction can be increased. Examples of increasing friction-the tyres of a motor car and bicycles are made rough to increase the friction .when a ground or surface become slippery after rain or water splashing it is made rough by spreading sand to increase the friction.

• ## Question: Why is it important to have friction?

Posted in: Physics | Date: 17/05/2018

A moving object will never stop if there is no friction. Actually it is important because it basically allows us to do everyday things: driving a car, picking up objects etc. Without it everything would just slip and slide, with nothing to grip onto. ... Friction "pushes" the wheels in a circular motion. If there is anything which moves forward with respect to something else while in contact with it without any external force acting it's because of god damn friction. ... Friction is evil: If there is external force available then the same friction slows it down.

• ## Question: What are some examples of uniform motion?

Posted in: Physics | Date: 17/05/2018

A car moving on a straight road without any change in its velocity is one of the examples. A Ball rolling on a floor without changing its velocity is again an example of uniform Motion.  Uniform motion is motion that "keeps the same form" over time.

• ## Question: Why is acetic acid is a weak acid?

Posted in: Chemistry | Date: 17/05/2018

Acetic acid (CH3COOH) is a carboxylic acid (RCOOH), and the majority of the carboxylic acids are weak acids, including acetic acid. This means that these acids dissociate partially into RCOO- anions and H+ cations in a given aqueous solution. Acetic acid is a weak acid. A strong acid is one that completely ionizes or dissociates in a solution ,provided there is sufficient solvent. In contrast, a weak acid only partially dissociates. Acids like acetic acid ( CH3COOH ) dissociates partially or incompletely, releasing only some of its hydrogen atoms into the solution.

• ## Question: Which is more acidic phenol or alcohol?

Posted in: Chemistry | Date: 17/05/2018

Both alcohols and phenols are weak acid the alcohols are less acidic than phenols because it is very tough to remove the H ion easily because phenoxide ion formed is stablised to some extent This is the negative charge on the oxygen atom around the ring . Alkyl group in alcohol don't have resonance.

• ## Question: Is acetic acid more acidic than benzoic acid?

Posted in: Chemistry | Date: 17/05/2018

The answer lies in the stability of the conjugate bases  formed by these two acids.

We only need to compare the point of difference among the two:

Benzoic acid : Ph-COO-

The phenyl ring has a minus I (inductive effect ) and also pulls the -ve charge density on oxygen atom through resonance. this leads to the formation of a stable conjugate base. so benzoic acid is quite acidic.

Acetic acid : CH3COO-

The methyl group has a plus I (inductive effect ) and pushes the electron cloud towards oxygen which already has a negative charge. This destabilizes the molecule and thus the acidity of the molecule and thus acetic acid is less acidic.

• ## Question: Which is more acidic phenol or carboxylic acid?

Posted in: Chemistry | Date: 17/05/2018

in case of phenols, negative charge is less effectively delocalized over one oxygen atom and less electronegative carbon atoms in phenoxide ion. Therefore, the carboxylate ion exhibits higher stability in comparison to phenoxide ion. Hence, the carboxylic acids are more acidic than phenols.

• ## Question: Why carboxylic acid is stronger than alcohol?

Posted in: Chemistry | Date: 17/05/2018

Resonance always stabilizes a molecule or ion, even if charge is not involved. The stability of an anion determines the strength of its parent acid. A carboxylic acid is, therefore, a much stronger acid than the corresponding alcohol, because, when it loses its proton, a more stable ion results. Hence phenol is less acidic than carboxylic acids

• ## Question: How do gas exerts pressure on the walls of container?

Posted in: Chemistry | Date: 17/05/2018

The molecules are continually colliding with each other and with the walls of the container. When a molecule collides with the wall, they exert small force on the wall The pressure exerted by the gas is due to the sum of all these collision forces.The more particles that hit the walls, the higher the pressure.

• ## Question: What do you mean by rectilinear motion?

Posted in: Physics | Date: 17/05/2018

Rectilinear motion means motion along a straight line. This is a useful topic to study for learning how to describe the movement of cars along a straight road or of trains along straight railway tracks.

• ## Question: What are the three different types of motion?

Posted in: Physics | Date: 17/05/2018

Types of motion in physics If we observe carefully,we will find that everything in the universe is in motion.However ,different objects move differently.Some objects move along a straight line,some move in a curved path,and some move in some other way.According to this we can say that there are three types of motion.Which are given as:

Translatory motion Rotatory motion Vibratory motion

• ## Question: What is debroglie hypothesis or statement?

Posted in: Physics | Date: 17/05/2018

De broglie hypothesis says that all matter has both particle and wave nature. The wave nature of a particle is quantified by de Broglie wavelength defined as $\lambda = \frac{h}{p}$ where $p$ is the momentum of the particle. This was called a hypothesis because there was no evidence for it when it was proposed, only analogies with existing theories. (The wavelength-momentum relation holds exactly for photons.)

Historically, de Broglie hypothesis was the next step in quantum theory after Planck, Einstein and Bohr.

In 1900, Max Planck introduced the notion that radiation is quantized to derive the black body radiation spectrum. In 1905, Albert Einstein used Planck's idea to explain photoelectric effect, which led to wide acceptance of the quantum nature of radiation. In 1913, Niels Bohr used quantization of radiation along with the Bohr hypothesis (that the angular momentum of electrons is quantized) to correctly predict the line spectrum of hydrogen atom and explain . In 1923, Lois de Broglie took this idea further and proposed that matter has wave nature as radiation has particle nature. Bohr hypothesis comes as an immediate consequence of de Broglie hypothesis - angular momentum must be conserved if an electron in an atom is seen as a wave going in circles around a nucleus such that the electron wave interferes constructively everywhere in the orbit.

In 1926 Erwin Schrödinger published the Schrödinger equation which generalized de Broglie's concept of matter waves and put them in a more robust theoretical footing.

The direct experimental confirmation came in 1927 when Clinton Davisson and Listor Germer and independently, GP Thomson observed electron diffraction.

• ## Question: Name the Taj trapezium.

Posted in: Chemistry | Date: 17/05/2018

Taj Trapezium Zone (TTZ) is a defined area of 10,400 sq km around the Taj Mahal to protect the monument from pollution. The Supreme Court of India delivered a ruling on December 30, 1996 regarding industries covered under the TTZ, in response to a PIL seeking to protect the Taj Mahal from environmental pollution. It banned the use of coal/ coke in industries located in the TTZ with a mandate for switching over from coal/ coke to natural gas, and relocating them outside the TTZ or shutting down. The TTZ comprises over 40 protected monuments including three World Heritage Sites i.e. the Taj Mahal, Agra Fort and Fatehpur Sikri. TTZ is so named since it is located around the Taj Mahal and is shaped like a trapezoid.

• ## Question: How can power loss be reduced?

Posted in: Physics | Date: 17/05/2018

To reduce energy loss, electricity generated in power stations is raised to a very high voltage for transmission. ... As the heating effect occurs when a current flows through cables with resistance, reducing the resistance of the transmission cables will reduce energy loss.

• ## Question: How a battery is made up?

Posted in: Physics | Date: 17/05/2018

Batteries have three parts, an anode (-), a cathode (+), and the electrolyte. The cathode and anode (the positive and negative sides at either end of a traditional battery) are hooked up to an electrical circuit. The chemical reactions in the battery causes a build up of electrons at the anode. he container of a typical alkaline battery, consisting of preform inserted into a steel can, also doubles as the cathode. The anode in the middle is a gel composed primarily of zinc powder. The separator between the anode and cathode is either paper or synthetic fiber that has been soaked in an electrolyte solution.

• ## Question: What are the advantages of friction?

Posted in: Physics | Date: 17/05/2018

ADVANTAGES OF FRICTION Friction plays a vital role in our daily life. Without friction we are handicap. 1. It is becomes difficult to walk on a slippery road due to low friction. When we move on ice, it     becomes difficult to walk due to low friction of ice. 2. We can not fix nail in the wood or wall if there is no friction. It is friction which holds the nail. 3. A horse can not pull a cart unless friction furnishes him a secure Foothold.

• ## Question: What is biosphere?

Posted in: Biology | Date: 17/05/2018

The regions of the surface and atmosphere of the earth or another planet occupied by living organisms. The biosphere, (from Greek bios = life, sphaira, sphere) is the layer of the planet Earth where life exists. ... The biosphere is one of the four layers that surround the Earth along with the lithosphere (rock), hydrosphere (water) and atmosphere (air) and it is the sum of all the ecosystems.

• ## Question: What is the importance of friction?

Posted in: Physics | Date: 17/05/2018

Although you normally hear about trying to reduce or eliminate friction, it actually has some important uses.

Since friction is a resistance force that slows down or prevents motion, it is necessary in many applications where you might want to hold items or do things and prevent slipping or sliding. In those cases, there is an advantage of having friction.

Quite often uses of frction can be seen from how things would be without friction. Without friction, you would not be able to walk, drive a car, or hold objects. Pens and pencils would not work.

Stopping a car or bike (brakes)

Questions you may have include:

How is friction important in walking? How is friction used in writing? How is friction important in vehicles?

This lesson will answer those questions. Useful tool: Units Conversion

Walking

You could not walk without the friction between your shoes and the ground. As you try to step forward, you push your foot backward. Friction holds your shoe to the ground, allowing you to walk. Consider how difficult it is to walk on slippery ice, where there is little friction.

Bear did not heed warning sign

Writing

Writing with a pencil requires friction. You could not hold a pencil in your hand without friction. It would slip out when you tried to hold it to write. The graphite pencil led would not make a mark on the paper without friction.

A pencil eraser uses friction to rub off mistakes written in pencil lead. Rubbing the eraser on the lead wears out the eraser due to friction, while the particles worn off gather up the pencil lead from the paper.

Driving a car or riding a bicycle

Your car would not start moving if it wasn't for the friction of the tires against the street. With no friction, the tires would just spin.

Likewise, you could not stop without the friction of the brakes and the tires.

• ## Question: How friction can be helpful?

Posted in: Physics | Date: 17/05/2018

Although you normally hear about trying to reduce or eliminate friction, it actually has some important uses.

Since friction is a resistance force that slows down or prevents motion, it is necessary in many applications where you might want to hold items or do things and prevent slipping or sliding. In those cases, there is an advantage of having friction.

Quite often uses of frction can be seen from how things would be without friction. Without friction, you would not be able to walk, drive a car, or hold objects. Pens and pencils would not work.

Stopping a car or bike (brakes)

Questions you may have include:

How is friction important in walking? How is friction used in writing? How is friction important in vehicles? This lesson will answer those questions. Useful tool: Units Conversion

Walking

You could not walk without the friction between your shoes and the ground. As you try to step forward, you push your foot backward. Friction holds your shoe to the ground, allowing you to walk. Consider how difficult it is to walk on slippery ice, where there is little friction.

Bear did not heed warning sign

Writing

Writing with a pencil requires friction. You could not hold a pencil in your hand without friction. It would slip out when you tried to hold it to write. The graphite pencil led would not make a mark on the paper without friction.

A pencil eraser uses friction to rub off mistakes written in pencil lead. Rubbing the eraser on the lead wears out the eraser due to friction, while the particles worn off gather up the pencil lead from the paper.

Driving a car or riding a bicycle

Your car would not start moving if it wasn't for the friction of the tires against the street. With no friction, the tires would just spin.

Likewise, you could not stop without the friction of the brakes and the tires.

• ## Question: What are the types of translatory motion?

Posted in: Physics | Date: 17/05/2018

TRANSLATORY MOTION  The motion in which all points of a moving body move uniformly along a straight line is called translatory motion. TYPES OF TRANSLATORY MOTION RECTILINEAR MOTION-If a body moves in a straight line it is called a Rectilinear motion.   CURVILINEAR MOTION-If a body moves along a curved path then it is said to have curvilinear motion.

• ## Question: What are the basic assumptions of kinetic theory of gases?

Posted in: Physics | Date: 17/05/2018

The basic assumptions of the kinetic theory of gases are as follows

• Gas is built of very tiny particles acquainted of molecules. The gas molecule sizes are very small compared to the gas container. So during any calculation, size of the gas molecules is considered as same that of the volume of the gas container.

• All gas molecules have equal mass.

• Statistical measurement can be applied on the gas molecules since the presence of huge number of molecules is there

• The molecular motions of gas molecules are random with constant velocity.

• The rapidly moving particles collide with each other and with the container. All these collisions are perfectly elastic. Therefore, the gas molecules are assumed to be perfectly elastic in nature and spherical in shape.

• The inter-ionic interactions between the gas molecules are negligible.

• Absolute temperature depends on the average kinetic theory of gases.

• Kinetic energy of the gas molecule is affected by the gravity since molecular mass is very low

• ## Question: What are the kinetic theory of gases?

Posted in: Physics | Date: 17/05/2018

The kinetic theory of gases are as follows

• Gas is built of very tiny particles acquainted of molecules. The gas molecule sizes are very small compared to the gas container. So during any calculation, size of the gas molecules is considered as same that of the volume of the gas container.

• All gas molecules have equal mass.

• Statistical measurement can be applied on the gas molecules since the presence of huge number of molecules is there

• The molecular motions of gas molecules are random with constant velocity.

• The rapidly moving particles collide with each other and with the container. All these collisions are perfectly elastic. Therefore, the gas molecules are assumed to be perfectly elastic in nature and spherical in shape.

• The inter-ionic interactions between the gas molecules are negligible.

• Absolute temperature depends on the average kinetic theory of gases.

• Kinetic energy of the gas molecule is affected by the gravity since molecular mass is very low

• ## Question: What does the kinetic theory state about the kinetic energy of gas molecules?

Posted in: Physics | Date: 17/05/2018

Gas molecules have a constant rapid motion which is randomness that rose from the collisions between the gas molecules. Gases have macroscopic properties like temperature, volume, pressure, thermal conductivity are explained by kinetic theory. Gas molecules move within the container with different velocities and collide with each other and exert a pressure on the wall of the container.

The basic assumptions of the kinetic theory of gases are as follows

• Gas is built of very tiny particles acquainted of molecules. The gas molecule sizes are very small compared to the gas container. So during any calculation, size of the gas molecules is considered as same that of the volume of the gas container.

• All gas molecules have equal mass.

• Statistical measurement can be applied on the gas molecules since the presence of huge number of molecules is there

• The molecular motions of gas molecules are random with constant velocity.

• The rapidly moving particles collide with each other and with the container. All these collisions are perfectly elastic. Therefore, the gas molecules are assumed to be perfectly elastic in nature and spherical in shape.

• The inter-ionic interactions between the gas molecules are negligible.

• Absolute temperature depends on the average kinetic theory of gases.

• Kinetic energy of the gas molecule is affected by the gravity since molecular mass is very low.

• ## Question: What are the basic assumptions of the kinetic molecular theory?

Posted in: Physics | Date: 17/05/2018

Gas molecules have a constant rapid motion which is randomness that rose from the collisions between the gas molecules. Gases have macroscopic properties like temperature, volume, pressure, thermal conductivity are explained by kinetic theory. Gas molecules move within the container with different velocities and collide with each other and exert a pressure on the wall of the container.

The basic assumptions of the kinetic theory of gases are as follows

• Gas is built of very tiny particles acquainted of molecules. The gas molecule sizes are very small compared to the gas container. So during any calculation, size of the gas molecules is considered as same that of the volume of the gas container.

• All gas molecules have equal mass.

• Statistical measurement can be applied on the gas molecules since the presence of huge number of molecules is there

• The molecular motions of gas molecules are random with constant velocity.

• The rapidly moving particles collide with each other and with the container. All these collisions are perfectly elastic. Therefore, the gas molecules are assumed to be perfectly elastic in nature and spherical in shape.

• The inter-ionic interactions between the gas molecules are negligible.

• Absolute temperature depends on the average kinetic theory of gases.

• Kinetic energy of the gas molecule is affected by the gravity since molecular mass is very low.

• ## Question: How does the kinetic molecular theory describe the behavior of a gas?

Posted in: Physics | Date: 17/05/2018

Kinetic Molecular Theory states that gas particles are in constant motion and exhibit perfectly elastic collisions. Kinetic Molecular Theory can be used to explain both Charles' and Boyle's Laws. The average kinetic energy of a collection of gas particles is directly proportional to absolute temperature only. The basic assumptions of the kinetic theory of gases are as follows • Gas is built of very tiny particles acquainted of molecules. The gas molecule sizes are very small compared to the gas container. So during any calculation, size of the gas molecules is considered as same that of the volume of the gas container. • All gas molecules have equal mass. • Statistical measurement can be applied on the gas molecules since the presence of huge number of molecules is there • The molecular motions of gas molecules are random with constant velocity. • The rapidly moving particles collide with each other and with the container. All these collisions are perfectly elastic. Therefore, the gas molecules are assumed to be perfectly elastic in nature and spherical in shape. • The inter-ionic interactions between the gas molecules are negligible. • Absolute temperature depends on the average kinetic theory of gases. • Kinetic energy of the gas molecule is affected by the gravity since molecular mass is very low.

• ## Question: Why is chloroacetic acid is stronger than acetic acid?

Posted in: Chemistry | Date: 17/05/2018

Chlorine being a strong electron withdrawing group, pulls the negative charge towards itself by inductive effect so that the negative charge density on the oxygen atom is reduced, hence stabilizing the conjugate base of chloroacetic acid. chloroacetic acid, ClCH2 COOH, in which the strongly electron-withdrawing chlorine replaces a hydrogen atom, is about 100 times stronger as an acid than acetic acid, and nitroacetic acid, NO2CH2 COOH, is even stronger.

• ## Question: What is oral hygiene?

Posted in: Biology | Date: 17/05/2018

Oral hygiene is the practice of keeping one's mouth clean and free of disease and other problems (e.g. bad breath) by regular brushing and cleaning between the teeth. ... The most common types of dental disease are tooth decay (cavities, dental caries) and gum diseases, including gingivitis, and periodontitis.

• ## Question: What are the postulates of the kinetic theory of gases?

Posted in: Physics | Date: 17/05/2018

Gas molecules have a constant rapid motion which is randomness that rose from the collisions between the gas molecules. Gases have macroscopic properties like temperature, volume, pressure, thermal conductivity are explained by kinetic theory. Gas molecules move within the container with different velocities and collide with each other and exert a pressure on the wall of the container.

The basic assumptions of the kinetic theory of gases are as follows

• Gas is built of very tiny particles acquainted of molecules. The gas molecule sizes are very small compared to the gas container. So during any calculation, size of the gas molecules is considered as same that of the volume of the gas container.

• All gas molecules have equal mass.

• Statistical measurement can be applied on the gas molecules since the presence of huge number of molecules is there

• The molecular motions of gas molecules are random with constant velocity.

• The rapidly moving particles collide with each other and with the container. All these collisions are perfectly elastic. Therefore, the gas molecules are assumed to be perfectly elastic in nature and spherical in shape.

• The inter-ionic interactions between the gas molecules are negligible.

• Absolute temperature depends on the average kinetic theory of gases.

• Kinetic energy of the gas molecule is affected by the gravity since molecular mass is very low.

• ## Question: Which one is more acidic phenol or acetic acid?

Posted in: Chemistry | Date: 17/05/2018

Acetic acid - 4.76 Phenol-10.02 Thus, we can say that  Pka phenol > Pka acetic acid OR ka phenol < ka acetic acid i.e. The acid dissociation constant for acetic acid is much than phenol. i.e.The amount of H+ released by Acetic acid is more than phenol. Thus acetic acid is more acidic than phenol. P.S. Acetate ion is much stabler than phenoxide ion- this fact is can also be explained by the same.

• ## Question: Is trichloroacetic acid a stronger acid than acetic acid?

Posted in: Chemistry | Date: 17/05/2018

When an chlorine atom, which is an electron withdrawing group is present in the chain attached to a carboxyl group, it exerts -I effect and withdraws electrons from the carbon of the carboxyl group as well as from the oxygen of the O-H bond. This decreases electron density at the oxygen atom of the O-H bond. Consequently, the O-H bond gets weakened and the release of H+ ion is favored. Moreover, the negative charge present on the carboxylate ion gets dispersed and its stability is increased. Thus, the acid strength of the acid increases. So now the H+ atom can easily come out and the stability of the carboxylate ion has also increased. Hence both the conditions make chloroacetic acid more acidic than acetic acid.

Inductive effect is responsible for the acidity of chloroacetic acid .

• ## Question: What is a balanced diet?

Posted in: Biology | Date: 17/05/2018

a diet consisting of a variety of different types of food and providing adequate amounts of the nutrients necessary for good health.

• ## Question: What are vectors?

Posted in: Biology | Date: 17/05/2018

A vector is a quantity or phenomenon that has two independent properties: magnitude and direction. The term also denotes the mathematical or geometrical representation of such a quantity.

Examples of vectors in nature are velocity, momentum, force, electromagnetic fields, and weight. (Weight is the force produced by the acceleration of gravity acting on a mass.) A quantity or phenomenon that exhibits magnitude only, with no specific direction, is called a scalar . Examples of scalars include speed, mass, electrical resistance, and hard-drive storage capacity.

• ## Question: What happens to your body when your body temperature rises?

Posted in: Physics | Date: 17/05/2018

When temperatures rise, the body reacts by increasing blood flow to the skin's surface, taking the heat from within the body to the surface. As the sweat evaporates, the body cools down.

• ## Question: What is the difference between real and ideal gas?

Posted in: Physics | Date: 17/05/2018

1.Ideal gas has no definite volume while real gas has definite volume.

2.Ideal gas has no mass whereas real gas has mass.

3.Collision of ideal gas particles is elastic while non-elastic for real gas.

4.No energy involved during collision of particles in ideal gas. Collision of particles in real gas has attracting energy.

5.Pressure is high in ideal gas compared to real gas.

6.Ideal gas follows the equation PV=nRT. Real gas follows the equation (P + a/V2) (V – b) = nRT.

• ## Question: What does the acronym optic stand for?

Posted in: Physics | Date: 17/05/2018

OPTIC Overview Parts Title Interrelationships and Conclusion Miscellaneous » OPTIC Overview Parts Title Interrelationship and Conclusion Miscellaneous »  OPTIC Ownership Professionalism Teamwork Innovation Client Miscellaneous »

• ## Question: What is meant by 'peptization' ?

Posted in: Chemistry | Date: 17/05/2018

Peptization is the process responsible for the formation of stable dispersion of colloidal particles in dispersion medium. In other words it may be defined as a process of converting a precipitate into colloidal sol by shaking it with dispersion medium in the presence of small amount of electrolyte.

• ## Question: What is the real color of the mirror?

Posted in: Physics | Date: 17/05/2018

As a perfect mirror reflects back all the colours comprising white light, it's alsowhite. That said, real mirrors aren't perfect, and their surface atoms give any reflection a very slight green tinge, as the atoms in the glass reflect back green light more strongly than any other colour.

• ## Question: What is the difference between an atom and a molecule?

Posted in: Chemistry | Date: 17/05/2018

An atom is smallest particle in an element that has the properties of the element. It is not possible to breakdown the atom further retaining the properties of the element. Atoms are not visible to the naked eye and are the basic building blocks. For example the atoms of element gold cannot be broken down further and each atom has the properties of gold.

Molecules are formed by the combination of two or more atoms. Unlike atoms, molecules can be subdivided to individual atoms. The atoms are bonded together in a molecule. Molecules also are not visible to the naked eye, while can be seen through highly magnifying microscopes and other scientific devices. Water is comprised of numerous water molecules. Each water molecule is made up of one oxygen atom and two hydrogen atoms. So a water molecule can be further divided into oxygen and hydrogen atoms. But these atoms cannot be subdivided. In a molecule, atoms are bonded together by single, double, or triple bonds.

An atom has a nucleus surrounded by electrons. The electrons are negatively charged particles. The nucleus contains neutrons and positively charged protons. Depending on the majority of the particles, the atom can be positively or negatively charged. When these charged atoms bond together to form molecules, the bonds are formed by the electrons filling up the outer orbits of the atoms. Since atoms exist independently, there is no bonding in an atom.

When atoms combine in different numbers to form a molecule, the end result can vary. For example, when two atoms of oxygen combine to form a molecule, it becomes O2 which is the oxygen we breathe in. But when three oxygen atoms combine to form an O3 molecule, it becomes Ozone. So another difference between atoms and molecules is that when similar atoms combine together in varying numbers, molecules of different properties can be formed. But when similar molecules combine together in any numbers, a simple product is formed.

A molecule is usually stable to exist by itself but an atom is not stable by itself. This is owing to the presence of electrons in the atoms. Only when sufficient number of electrons are present in an atom, it becomes stable. The sufficient number of electrons are received in an atom, when two atoms bond together and share the electrons. Thus it becomes stable and forms a molecule. Not all atoms can bond together. The bonding depends on the charge and chemical properties of the atoms.

Atoms and molecules are present in all objects and living things. The composition and density levels vary the thickness and form of the objects. In gases, the molecules are very loosely packed so that the molecules can flow around easily without colliding. In liquids, the packing is a bit more compact and so the particles are always together. But in solids the packing is very compact and hardly any movement to the molecules is allowed, giving the object a firm shape.

• ## Question: What do we do with oxygen in our body?

Posted in: Chemistry | Date: 17/05/2018

The human body requires oxygen to function. It takes in oxygen and releases waste gas in the form of carbon dioxide. This two-part process is called respiration. There are two types of respiration: anaerobicand aerobic. Anaerobic respiration doesn’t use oxygen and is mainly a function of simple, one-celled organisms. Aerobic respiration is what humans and animals use. In aerobic respiration, oxygen is used within the cell to help create energy.

When you breathe, air enters microscopic air sacs in your lungs called alveoli. Oxygen passes through the walls of the alveoli and into the bloodstream. The blood carries oxygen to cells throughout the body, where it helps convert nutrients into usable energy. Fun fact: oxygen is what makes your blood red. Blood without oxygen appears blue.

Respiration is a metabolic process. The body does not store oxygen; its supply is constantly replenished through respiration. That’s why it’s important that the air you breathe contains ample oxygen. The more active brody processes are, the more oxygen they require. A higher oxygen content enables the body’s cells and processes to perform at a higher rate. This means that the body’s capabilities increase when more oxygen is available.

• ## Question: What is meant by the term “Magnetic field lines”? List any two properties of...

Posted in: Physics | Date: 17/05/2018

The magnetic field direction is the same direction a compass needle points, which is tangent to the magnetic field line at any given point. ... Magnetic field lines are continuous and unbroken, forming closed loops. Magnetic field lines are defined to begin on the north pole of a magnet and terminate on the south pole. Properties:

They always form closed loops. No two magnetic lines intersect. Outside they seems to travel from north to south and inside south to north. They leave NORTH pole and enter SOUTH pole normally. It is vector quantity. The magnetic field lines are crowded near the pole where the field is strong and far from the magnet where the field is weak. In case the field lines are parallel and equidistant, they represent a uniform magnetic field. The Earth’s’ magnetic field is a uniform limited space.

• ## Question: What are the physical and chemical properties?

Posted in: Chemistry | Date: 17/05/2018

A physical property is an aspect of matter that can be observed or measured without changing its chemical composition. Examples of physical properties include color, molecular weight and volume.

A chemical property may only be observed by changing the chemical identity of a substance. In other words, the only way to observe a chemical property is by performing a chemical reaction. This property measures the potential for undergoing a chemical change. Examples of chemical properties include reactivity, flammability and oxidation states.

• ## Question: How would Hess's law be useful?

Posted in: Chemistry | Date: 17/05/2018

Hess's law allows the enthalpy change (ΔH) for a reaction to be calculated even when it cannot be measured directly. This is accomplished by performing basic algebraic operations based on the chemical equations of reactions using previously determined values for the enthalpies of formation.

Hess' Law allows us to take a theoretical approach to considering enthalpy changes where an empirical one is either impossible or impractical.

Explanation:

Consider the reaction for the hydration of anhydrous copper (II) sulfate:

CuSO4+5H2O→CuSO4⋅5H2O

This is an example of a reaction for which enthalpy change cannot be calculated directly. The reason for this is that water would have to perform two functions - as a hydrating agent and as a temperature gauge - at the same time and in the same water sample; this is not doable.

We can, however, measure the enthalpy changes for the solvation of anhydrous copper (II) sulfate and that of hydrated copper (II) sulfate and, thanks to Hess' Law, we are able to use this data to calculate the enthalpy change of our original hydration.

Using data from two reactions rather than one does double the uncertainty, and calorimetry often carries gross inefficiencies - especially in the school laboratory; however, this method is our only option given that we would not otherwise be able to obtain our desired data.

• ## Question: What are the different process for purification of water?

Posted in: Chemistry | Date: 17/05/2018

Screening

Water from lakes, rivers or the ground passes through a screen as it enters the water treatment plant. When the water source is a lake or river, the screen serves an important function, keeping out large natural contaminants such as plants and wood, or fish. If ground water is used, screening may not be necessary since the water has passed through layers of the earth in what is essentially a natural screening function.

Coagulation

Treatment plant workers add alum and other chemicals to the water, which cause tiny sticky particles, or floc, to form. These floc attract dirt particles, making them eventually heavy enough to sink to the bottom of the water storage tank.

Sedimentation

The water and floc flow into a sedimentation basin. As the water sits there, the heavy floc settle to the bottom, where they remain until removal.

Filtration

Water passes through layers of gravel, sand and perhaps charcoal, which serve to filter out any remaining particles. The gravel layer is often about 1 foot deep and the sand layer about 2½ feet deep.

Disinfection

Water goes into a closed tank or reservoir. Chlorine or other disinfecting chemicals kill any remaining microorganisms or bacteria in the water and help keep the water clean until distribution. If a water treatment facility uses ground water as its only water source, disinfection may be the only step required to sufficiently treat the water. After it is disinfected, the purified water sits in the closed tank or reservoir until it flows through pipes to homes and businesses.

• ## Question: What are the drawbacks of Bohr's Atomic Model?

Posted in: Chemistry | Date: 17/05/2018

1.Bohr treated electrons as particles where according to de Broglie's hypothesis, having a very low mass, electron also exhibits wave nature.

2. Bohr's model was adequate only for nucleus having only one electron e.g. Hydrogen, He+1, Li+2 etc. Bohr's model could not explain the spectra of multi-electronic atoms.

3. Bohr's model was two-dimensional where an atom is three-dimensional.

4. Using a better spectrometer, the spectra showed very fine lines. Bohr's model could not explain the origin of those fine lines. (Solved by Arthur Sommerfield who imagined electrons orbiting in different planes and having elliptical orbits.)

5. Bohr's model could not explain the effect electric field and magnetic field on spectra. (Stark effect and Zeeman effect)

6. In Bohr's equation, the momentum and position of electron, revolving around the nucleus were well defined. But, according, Heisenberg's Uncertainty principle, it is impossible to measure the position and momentum of electrons precisely. If the position is measure with maximum precision, there will be uncertainty in the value of momentum and vice versa.

• ## Question: What are the limitations of Dalton's atomic theory?

Posted in: Chemistry | Date: 17/05/2018

Dalton's atomic theory was the first milestone towards the inner structure of matter. It gave a powerful initiative to the scientists about the study of matter during 19th century. It held the ground for about a century. But the brilliant researches conducted in the beginning of 20th century by Sir J.J Thomson, Lord Rutherford, Neils Bohr and others have revolutionised our knowledge about the structure of atom. The main drawbacks of Dalton's Atomic Theory are:

(i) It could explain the laws of chemical combination by mass but failed to explain the law of gaseous volumes.

(ii) It could not explain why atoms of different elements have different masses, sizes, valencies, etc.

(iii) Why do atoms of the same or different elements combine at all to form molecules

(iv) What is the nature of binding force b/w atoms and molecules which accounts the existence of matter in three states, i.e., solids, liquids, and gases ?

(v) It makes no distinction b/w the ultimate particles of an element or a compound

• ## Question: what is greenhouse effect, and what are its causes?

Posted in: Chemistry | Date: 17/05/2018

The Earth’s surface warms up during the day and cools down at night, releasing the heat in the form of infrared radiation IR out of the atmosphere into space. But before all these infrared radiation can escape out of the atmosphere into the space, they are absorbed by greenhouse gases (GHG’s) present in the atmosphere. The absorption of these radiations by greenhouse gases makes it possible to keep this planet warm for humans. Without Greenhouse effect, the temperature of this planet would be lesser by 30 degree Celsius and this would be too cold for us to survive.

Causes of the Greenhouse Effect

1. Burning of Fossil Fuels: Fossil fuels like coal, oil and natural gas have become an integral part of our life. They are used on large basis to produce electricity and for transportation. When they are burnt, the carbon stored inside them is released which combines with oxygen in the air to create carbon dioxide. With the increase in the population, the number of vehicles have also increased and this has resulted in increase in the pollution in the atmosphere. When these vehicles run, they release carbon dioxide, which is one the main gas responsible for increase in greenhouse effect.

Apart from that, electricity-related emissions are high because we are still dependent on coal for electricity generation which releases large amount of CO2 into the atmosphere and is still the primary source of fuel for generating electricity. Although, renewable sources are catching up, but it may take a while before we can reduce our dependance on coal for electricity generation.

2. Deforestation: Forests hold a major green area on the planet Earth. Plants and trees intake carbon dioxide and release oxygen, through the process of photosynthesis, which is required by humans and animals to survive. Large scale development has resulted in cutting down of trees and forests which has forced people to look for alternate places for living. When the wood is burnt, the stored carbon in converted back into carbon dioxide.

3. Increase in Population: Over the last few decades, there have been huge increase in the population. Now, this has resulted in increased demand for food, cloth and shelter. New manufacturing hubs have come up cities and towns that release some harmful gases into the atmosphere which increases the greenhouse effect. Also, more people means more usage of fossil fuels which in turn has aggravated the problem.

4. Farming: Nitrous oxide is one the greenhouse gas that is used in fertilizer and contributes to greenhouse effect which in turn leads to global warming.

• ## Question: Which compounds are obtained from minerals?

Posted in: Chemistry | Date: 17/05/2018

Minerals composed of compounds are simply referred to as minerals (i.e., quartz, which is made up on silicon and oxygen

• ## Question: What can produce a magnetic field?

Posted in: Physics | Date: 17/05/2018

All magnetic fields are created by moving charged particles. Even the magnet on your fridge is magnetic because it contains electrons that are constantly moving around inside. The first indication that moving electric charges cause magnetic fields was discovered in the early 19th century. During an experiment, it was observed that when an electric current flowed through a wire, a nearby compass would change direction. An electromagnet is a magnet that uses an electric current to generate its magnetic field. This differs from permanent magnets, like the ones on your refrigerator, which rely on the magnetic properties of the atoms in the material to create a magnetic field. At this point, our electromagnet is just a wire, but the magnetic field is too weak to do anything practical. However, if we bend the wire around and around to form a coil, the magnetic fields of the loops will concentrate in the center.

• ## Question: What is a chemical change of matter?

Posted in: Chemistry | Date: 17/05/2018

Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. Some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. Understanding chemical changes is a major part of the science of chemistry. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an energy change as new products are generated. An example of a chemical change is the reaction between sodium and water to produce sodium hydroxide and hydrogen. So much energy is released that the hydrogen gas released spontaneously burns in the air. This is an example of a chemical change because the end products are chemically different from the substances before the chemical reaction.

The following can indicate that a chemical change has taken place:

Change of odor. Change of color (for example, silver to reddish-brown when iron rusts). Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat. Change of composition - paper turning to ash when burned. Light and/or heat given off. Formation of gases, often appearing as bubbles in liquids. Formation of a precipitate (insoluble particles). The decomposition of organic matter (for example, rotting food). The change is difficult or impossible to reverse

• ## Question: What is the atomic structure of an atom?

Posted in: Chemistry | Date: 17/05/2018

Atoms consist of electrons surrounding a nucleusthat contains protons and neutrons. Neutrons are neutral, but protons and electrons are electrically charged. Protons have a relative charge of +1, while electrons have a relative charge of -1. The number of protons in an atom is called its atomic number [Image result for What is the atomic structure of an atom?]

• ## Question: What did the gold foil experiment show about the atom?

Posted in: Chemistry | Date: 17/05/2018

Rutherford's gold foil experiments (and other metal foil experiments) involved firing positively charged alpha particles at a piece of gold/metal foil. The alpha particles that were fired at the gold foil were positively charged. Most of the time, the alpha particles would pass through the foil without any change in their trajectories, which is what was expected if JJ Thomson's plum pudding model of the atom was correct. However, occasionally the alpha particles would be deflected to some degree, and sometimes an alpha particle would bounce back directly toward the experimenter. Rutherford likened this to firing a 15-inch artillery shell at a sheet of tissue paper and the shell came back to hit you.

• ## Question: What are the chemical and physical properties of water?

Posted in: Chemistry | Date: 17/05/2018

Physical properties of water

Water is colorless and tasteless liquid. The molecules of water have extensive hydrogen bonds resulting to unusual properties in the condensed form. This also leads to high melting and boiling points. As compared to other liquids, water has a higher specific heat, thermal conductivity, surface tension, dipole moment etc. These properties form the reason for its significance in the biosphere. Water is an excellent solvent and therefore it helps in the transportation of ions and molecules required for metabolism. It has a high latent heat of vaporization which helps in the regulation of body temperature.

Chemical properties of water

Water reacts with a lot of substances to form different compounds. Some significant reactions are as follows:

Amphoteric nature:

Water can act as both acid and base, which means that it is amphoteric in nature. Example: Acidic Behavior:               H2O(l)+NH3(aq) ⇌ H3O+(aq)+NH+4(aq) Basic Behavior:                 H2O(l)+H2S(aq)   ⇌    H3O+(aq)+HS−(aq)

Redox reactions:

Electropositive elements reduce water to hydrogen molecule. Thus water is a great source of hydrogen. Let us see an example in this case:

2H2O(l)+2Na(s)→2NaOH(aq)+H2(g)

During the process of photosynthesis, water is oxidized to O2. As water can be oxidized and reduced, it is very useful in redox reactions.

Hydrolysis reaction

Water has a very strong hydrating tendency due to its dielectric constant. It dissolves many ionic compounds. Some covalent and ionic compounds can be hydrolyzed in water.

• ## Question: What was the alpha particle experiment?

Posted in: Chemistry | Date: 17/05/2018

The experiment involves firing alpha particles, positively charged helium nuclei made of two protons and two neutrons, at a thin layer of gold foil. There is a screen behind the gold foil which is used as a detector to detect any particles that have passed through the foil. The alpha particles are fired in a thin stream at the foil.

The results of the experiment showed that most of the alpha particles passed straight through the gold foil, even though it looks as though the alpha particles are being fired at a solid surface. This shows that most of the gold atoms are actually empty space. Some of the alpha particles were deflected slightly, meaning that there must be a small part of the gold atom that is positively charged. This is because the alpha particles are positive and like charges repel each other, so the positive part of the nucleus deflected the alpha particles. A very small amount were deflected by more than 90 degrees meaning this positive part must be very dense. The small, dense, positive centre was named the nucleus. So the Rutherford experiment shows us that atoms have nuclei.

• ## Question: Can you demagnetize a neodymium magnet?

Posted in: Physics | Date: 17/05/2018

A magnet that has had irreversible losses could theoretically be re-magnetized to the original strength, or very close to it. (K&J Magnetics does not offer re-magnetization services for demagnetized magnets.) ... For neodymium magnets, this temperature is very high, typically above 900°C to 1000°C.

• ## Question: What resistor do I need to reduce voltage?

Posted in: Physics | Date: 17/05/2018

To reduce voltage in half, we simply form a voltage divider circuit between 2 resistors of equal value (for example, 2 10KΩ) resistors. To divide voltage in half, all you must do is place any 2 resistors of equal value in series and then place a jumper wire in between the resistors.

• ## Question: Why are zeolites good shape selective catalysts?

Posted in: Chemistry | Date: 17/05/2018

Small and uniform pores characterize zeolite catalysts. If most catalytic sites are inside this pore structure and if the pores are small, the fate of reactant molecules and the probability of forming product molecules are determined mostly by molecular dimension and configuration.

• ## Question: What is the formula for power output?

Posted in: Physics | Date: 17/05/2018

The standard metric unit of power is the Watt. As is implied by the equation for power, a unit of power is equivalent to a unit of work divided by a unit of time. Thus, a Watt is equivalent to a Joule/second.

• ## Question: How does a resistor reduce current?

Posted in: Physics | Date: 17/05/2018

Resistor is like a current limiter. It limits the amount of current flowing through a device.

Suppose you have to apply a certain current of 5 amperes to a device input and you have 10 amperes source so what would you do ?

solution : Add a resistor in series to limit the current.

This resistance will create a voltage drop (reduces voltage in that area or drops potential) thus reducing the current passing through it.

Current is defined as amount of charge flowing in a given time so you basically limit the flow of electrons (or you RESIST the flow of electrons). In the process of limiting the flow of current and reducing voltage, a resistor absorbs electrical energy, which is released in the form of heat.

If you break one resistor , and scratch off the outer coating of insulating paint, you might see an insulating ceramic rod running through the middle with copper wire wrapped around the outside. A resistor like this is described as wire-wound. The number of copper turns controls the resistance very precisely: the more copper turns, and the thinner the copper, the higher the resistance. In smaller-value resistors, designed for lower-power circuits, the copper winding is replaced by a spiral pattern of carbon. Resistors like this are much cheaper to make and are called carbon-film. Generally, wire-wound resistors are more precise and more stable at higher operating temperatures.

• ## Question: How do you read the value of a resistor?

Posted in: Physics | Date: 17/05/2018

Steps Position the resistor with the gold or silver color band to the right.. Read the color sequence that must be decoded to determine resistance. ... Determine the coded number for the resistive value. ... Determine the tolerance of the resistor. ... Determine the decoded number for the resistive value.

• ## Question: Define the term 'amorphous'. Give a few examples of amorphous solids.

Posted in: Chemistry | Date: 17/05/2018

The substance whose constituent are arranged in an irregular manner are called as amorphous solids.They lack shape or form unlike crystalline solids.These substances are incompressible & rigid. For example glass, rubber, plastic.

• ## Question: What is the significance of meiosis?

Posted in: Biology | Date: 17/05/2018

The significance of meiosis :-

1. It maintains the same chromosome n umber in the sexually reproducing organisms. From a diploid cell, haploid gametes are produced which in turn fuse to form a diploid cell.

2. It restricts the multiplication of chromosome number and maintains the stability of the species.

3. Maternal and paternal genes get exchanged during crossing over. It results in variations among the offspring.

4. All the four chromatids of a homologous pair of chromosomes segregate and go over separately to four different daughter cells. This leads to variation in the daughter cells genetically.

• ## Question: Why do batteries die out?

Posted in: Physics | Date: 17/05/2018

When the active material in the plates can no longer sustain a discharge current, a battery "dies". Normally a car (or starting) battery "ages" as the active positive plate material sheds (or flakes off) due to the normal expansion and contraction that occurs during the discharge and charge cycles.

After so many cycles (charge/discharge), the plates on batteries experience irregular growth, crack from water loss in the chemical reaction, or shed into the electrolyte and cannot produce the necessary power. AGM batteries experience irreversible acid stratification which lowers power. In short, the batteries die from variables that happen with repeated use. Things that speed up the "death" of a battery are extreme temperatures, larger loads on the battery, and charging errors. Roughly 80% of battery damage occurs due to improper charger use or unregulated chargers.

• ## Question: Explain Interstitials:

Posted in: Chemistry | Date: 17/05/2018

Interstitial: Pertaining to being between things, especially between things that are normally closely spaced. The word interstitial is much used in medicine and has specific meaning, depending on the context. For instance, interstitial cystitis is a specific type of inflammation of the bladder wall. Interstitial radiation involves placing radioactive material directly into a tumor. Interstitial pneumonia is inflammation of the lung that involves the mesh of lung tissue (alveolar septa) rather than the air spaces (alveoli

• ## Question: What are some examples of acceleration?

Posted in: Physics | Date: 17/05/2018

speeding up, slowing down and turning are all examples of acceleration. A simple example would be dropping a ball: as it falls its speed increases, which is a type of acceleration. A more complicated example would be standing in a circular, rotating space station.

• ## Question: What is the formula for acceleration?

Posted in: Physics | Date: 17/05/2018

Acceleration is a measure of how quickly the velocity of an object changes. So, the acceleration is the change in the velocity, divided by the time. ... The units for acceleration are meters per second squared (m/s2).  Therefore,   acceleration = velocity/time

• ## Question: What are the advantages and disadvantages of wave energy?

Posted in: Chemistry | Date: 17/05/2018

Advantages of wave power Clean and green Because it uses only the energy of ocean waves, wave energy does not produce greenhouse gases or other pollutants like fossil fuels do.   Renewable and reliable Waves are a material that cannot be used up like other conventional forms of energy such as oil, natural gas, and coal, and we won’t run out of waves any time soon. Waves will continue to hit coastlines worldwide, and therefore, they can serve as a reliable source of energy.   Worldwide potential With an estimated worldwide electricity-generating potential of 2 terawatts (TW) from waves, there are many opportunities to develop this technology into one of many resources for our renewable energy future.   Efficient energy production The energy density of waves along shorelines is approximately 30-40 kW/m of waves, and further out into the ocean, most waves can generate 100 kW/meter of electricity. Less than ½ mile2 of ocean has the potential to generate more than 30 MW of power, which is enough energy to power 20,000 British homes.   Can be built offshore While wave energy devices can be built near shorelines, they can also be built offshore, which reduces shoreline conflicts of use such as recreation and fishing.   Low operation costs Once they have been built, wave energy devices can be free to operate by themselves, unless the equipment malfunctions or damage occurs.   Minimum visual impact Wave energy devices can be installed to be mostly or entirely submerged beneath the water. The devices can be installed far enough from shore to allow for minimal visual impact.   No fuel cost Because wave energy uses no fuel, this dramatically lowers the cost of device operation.   No pollution or death Unlike oil spills and pollution and death from fossil fuels like coal, there is virtually no pollution from the generation of electricity from waves.   Size advantage Wave energy devices can be tailored to meet electricity demand, and therefore can be manufactured at different sizes that are appropriate for each location. In contrast, fossil fuels generally require large facilities in order to produce electricity.   Disadvantages of wave power Current high cost of investment Because wave energy is still in the developmental stage, it is very costly to build wave devices. As the technology improves and the demand for renewable energy technologies increases, the costs of investment and construction of wave energy technology are expected to decrease.   Maintenance and weather effects Equipment that is exposed to rugged oceanic conditions 24/7 can lead to damage to wave equipment and to corrosion from salty seawater, requiring maintenance. Oceanic storms such as hurricanes are particularly damaging to wave equipment.   Marine life impacts Marine life may be harmed or displaced, or their habitats negatively impacted by the construction of wave energy devices.   Reduced sea usage The physical presence of wave energy device “farms” could potentially reduce the size of shipping channels, as well as opportunities for recreation and fishing.   Few implemented Thus far, only a few pilot wave energy projects have been constructed globally. Further research is necessary to determine the the lifespan of the equipment, the associated costs with running the devices, and the impacts of these machines on both human and marine life.   Noise Constantly running wave energy devices can be much noisier than waves are naturally, and this could potentially be disruptive to both humans and sea life living near these devices.   Slow technology improvements Wave energy has been developing since the 1700s, and yet it is still a nascent technology that needs to be more fully developed. This slow development is an impediment to investment in this type of renewable energy.   Difficult to transmit wave energy It is currently very challenging to transport ocean wave-generated electricity long distances to where it will be consumed inland.   Visual impacts For those people living near ocean shorelines, some types of wave energy devices can be unsightly and interfere with ocean views.

• ## Question: What is biofuel in simple terms?

Posted in: Chemistry | Date: 17/05/2018

A biofuel is any liquid fuel derived from biological material such as trees, agricultural wastes, crops, or grass. Biofuel can be produced from any carbon source that can be replenished rapidly, such as plants. Biofuels are used globally and biofuel industries are greatly expanding in Europe, Asia, and North and South America. They contain no sulfur and produce low carbon monoxide and toxic emissions. Biofuels are substitutes for conventional fossil fuels, such as petroleum, propane, coal, and natural gas. Common U.S. agricultural products including switchgrass and soybeans are specifically grown for biofuel production. Biofuels can reduce greenhouse gas emissions and increase energy security by providing an alternative to fossil fuels. By 2050, biofuels could reduce our greenhouse gas emissions by 1.7 billion tons per year—equivalent to more than 80% of current transportation-related emissions.

• ## Question: What is troponin and tropomiysin?

Posted in: Biology | Date: 17/05/2018

Troponin is attached to the protein tropomyosin and lies within the groove between actin filaments in muscle tissue. In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, thus preventing contraction.

• ## Question: What is the magnitude of the acceleration?

Posted in: Physics | Date: 17/05/2018

The magnitude of the acceleration vector along the path is the time rate of change of speed.

• ## Question: What are the strongest rare earth magnets?

Posted in: Physics | Date: 17/05/2018

Neodymium magnets, invented in the 1980s, are the strongest and most affordable type of rare-earth magnet. They are made of an alloy of neodymium, iron, and boron (Nd2Fe14B), sometimes abbreviated as NIB

• ## Question: What are the advantages of friction?

Posted in: Physics | Date: 17/05/2018

ADVANTAGES OF FRICTION Friction plays a vital role in our daily life. Without friction we are handicap. 1. It is becomes difficult to walk on a slippery road due to low friction. When we move on ice, it     becomes difficult to walk due to low friction of ice. 2. We can not fix nail in the wood or wall if there is no friction. It is friction which holds the nail. 3. A horse can not pull a cart unless friction furnishes him a secure Foothold.

• ## Question: Which is more acidic phenol or alcohol?

Posted in: Chemistry | Date: 17/05/2018

alcohols and phenols are weak acid the alcohols are less acidic than phenols because it is very tough to remove the H ion easily because phenoxide ion formed is stablised to some extent This is the negative charge on the oxygen atom around the ring . Alkyl group in alcohol don't have resonance

• ## Question: Why formic acid is more acidic than benzoic acid?

Posted in: Chemistry | Date: 17/05/2018

Formic acid is stronger than benzoic acid because it has a lower pKa value (formic acid pKa = 3.751; benzoic acid pKa = 4.204; Acid dissociation constant).

As to why this happens, I believe a look at the structures may shed some light.

Formic acid has a C-H bond on the α Carbon atom (the Carbon in the -COOH group). Benzoic acid has a C-C bond on the same atom.

Now the C=O bond and the C-O(-) (the negative sign indicates that the H has left the -OH group in the acid) are quite important here. The C atom that is double bonded to the O atom is quite electron deficient and has a partial positive charge on it (because O is highly electronegative). This electron deficient C atom has to stabilise itself by attracting electrons from either one of the two single bonds on it. One of them is the C-O(-) bond which has a O(-) at one end that needs to be stabilised too; while the other single bond is either a C-H single bond or a C-C single bond where the other C atom is a part of an aromatic ring.

The C-H single bond cannot satisfy the electron deficiency at the α C atom as efficiently as the C-C single bond attached to an aromatic ring. So, the α C atom of benzoic acid can satisfy its electron deficiency by delocalising it over the aromatic ring and, therefore, doesn't need to satisfy it by delocalising the negative charge on the O atom of the -COOH group.

However, in formic acid, the α C atom has no such choice and is forced to satisfy its electron deficiency by delocalising the negative charge of the O atom of the -COOH group.

As we know, more delocalisation of charges leads to more stable structures. Since the negative charge on the O atom is more delocalised in the HCOOH molecule than in the C6H5-COOH molecule, therefore, formic acid is stronger than benzoic acid.

• ## Question: What is the Ka of formic acid?

Posted in: Chemistry | Date: 17/05/2018

The ionisation constant (Ka) of formic acid can be calculated by the following formula;-

Ka = {[H+] * [HCOO-]} / [HCOOH]

Therefore you would need to know the value of each of the three concentration values on the right-hand side of the equation.

The equation for the dissociation of formic acid is;-

HCOOH ⇌ H+ + HCOO-

From this equation it can be seen that, at any degree of ionisation, the moles of H+ ions produced is equivalent to the moles of HCOO- ions. Therefore we can say that;-

[H+] = [HCOO-]

So, the equation for Ka in this case becomes;-

Ka = {[H+] * [H+]} / [HCOOH]

Ka = [H+]^2 / [HCOOH]

So, we have simplified our Ka formula down to two values, the H+ ion concentration [H+], and the concentration of undissociated formic acid [HCOOH]. To calculate the Ka for formic acid, we therefore need to either measure, or be given these values.

For example, if we started with a solution of formic acid which was 0.1M, we could measure its pH. Since pH = -log[H+], we could then calculate the H+ ion concentration and solve the Ka equation.

As it turns out the pH of a 0.1M formic acid solution is 2.38. Therefore, for this formic acid solution;-

-log([H+]) = 2.38

log([H+]) = -2.38

[H+] =10^(-2.38)

[H+] = 0.0042 M

Also, since formic is a relatively weak acid we can use the original solution concentration. i.e. [HCOOH] = 0.1M

Now we can solve the Ka equation we simplified above;-

Ka = [H+]^2 / [HCOOH]

Ka = (0.0042 )^2 / 0.1

Ka = 1.764 * 10^-4

• ## Question: What temperature in Kelvin scale is equal to 60 degree celsius

Posted in: Chemistry | Date: 17/05/2018

T(K)=T(Celsius) + 273.15

so, for 60 deg c

T(k)=60+273.15

= 333.15 K

• ## Question: 4 men and 6 women finish a job in 8 days, while 3 men and 7 women finish it in 1...

Posted in: Mathematics | Date: 17/05/2018

Let m be a man's one day effort and w be a woman's one day effort.  4m+6y=1/8  3m+7y=1/10  10y=1/x => x=1/10y  12m+18y=3/8  12m+28y=4/10  => 10y = 4/10-3/8 => 10y = 1/40  Hence x = 40 days.

• ## Question: what is glacier? name the glacier from which ganga originates?

Posted in: Social Studies | Date: 17/05/2018

A slowly moving mass or river of ice formed by the accumulation and compaction of snow on mountains or near the poles. It originate from gangotri glacier at gomukh in uttrakhand state of India by the name bhagirathi. At Devprayag when bhagirathi river joins the alaknanda then it is called the ganga

• ## Question: Why is a carboxylic acid more acidic than a phenol?

Posted in: Chemistry | Date: 17/05/2018

Carboxylic acid are more acidic than phenols because the negative charge in carboxylate anion is more spread out as compared to the phenoxide ion as there are two electronegative O-atoms in carboxylate anion in comparison to one in phenoxide ion.

• ## Question: In which state wild ass and camel found ?

Posted in: Geography | Date: 05/02/2020

Gujrat