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Myopia is a defect in one's eye when that person is not able to see things clearly that are at a distance. It is also called as shortsightedness or nearsightedness. Basically in this situation the light that comes and get focused on our retina gets shifted i.e. it gets focused in front of the retina. So to correct it concave lens is used. As concave lens diverge the incoming light hence it gets focused right on our retina.

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From name you can easily differentiate the two, first that Half Wave Rectifier converts the AC input into pulsating unidirectional DC for Half the time period of the input i.e. if a positive input ranging from 0 to 180 degree is given only 0 to 90 degree will be seen on the output side. On the other hand for Full Wave Rectifier you will get output for the entire time period so the RMS voltage obtained in both is different due to their working cycle. Another difference is that half wave rectifier efficiency is less compared to full wave as there RMS voltages are different.

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Pure semiconductor resistivity and resistance lies between conductors and insulators. And semiconductors show or have a negative temperature coefficient of resistivity, this means that as temp increases its resistivity decreases in turn result in the decrease in resistance and hence  the conductivity increases. But if the temperature decreases the resistivity and resistance increase and conductivity decrease. As according to Energy Band Gap theory the Energy gap is given by following formula:-

E=1.21 - (3.6*10^-4* T) eV...for Si

T= absolute temperature in kelvin

so as temp increases the energy band decreases and we require less energy to shift electron from valence band to conduction band hence enhancing the conductivity.

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As semiconductors show or have a negative temperature coefficient of resistivity, this means that as temp increases its resistivity decreases in turn result in the decrease in resistance and hence  the conductivity increases. But if the temperature decreases the resistivity and resistance increase and conductivity decrease. As according to Energy Band Gap theory the Energy gap is given by following formula:-

E=1.21 - (3.6*10^-4* T) eV...for Si

T= absolute temperature in kelvin

so as temp increases the energy band decreases and we require less energy to shift electron from valence band to conduction band hence enhancing the conductivity.

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Problem for setting up wind plants are, first there should be proper wind flow in a particular area and to detremine that it takes almost 1 year analyse that. Another porblem is the topographical and land issues there might be some sites with great wind potential but the land can be disputed or may come under forest or any sanctuary. So getting proper land is also a main issue. With water based plants i.e. hydro power plants is finding a river with water availability all year long and the land near it. If there is any settlement near the location they have to relocate it, that is one of the biggest problem. Another is the environment issue for hydro power plants.

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In solar water heater the heat energy from sun is utilised to heat water. In this the water to be heated is passed through copper coils or pipes and those are coated black. As black absorbes most heat than any other color it and copper is the best conductor of heat this to properties help the water to get heat up quickly.

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Artificial satellites orbit around earth in basically to orbits i.e. equatorial and polar. Equatorial orbits means it's along the equator of the earth the satellite orbit earth latitudinally. On the other hand satellites orbitting in polar axis orbit from pole to pole i.e. longitudinally.

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This will happen in normal condition but if we do it in vaccum both will fall with same speed and will reach ground at same time. In normal condition sheet of paper experience drag due to air i.e. air will resist it but if we crumpled it into a ball that drag or air resistance is reduce and hence it will fall faster that sheet of paper.

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L-C oscillations are not realistics because and element whether its an inductor or capacitor have some lossy element i.e. resistance. An inductor is made of coil and coil have some resistance same capacitor is also have some resistance. During L-C oscillations the due to this resistance enegry dissipation will occur and slowly the ocsillations will die out. So practically L-C oscillations will not occur for intinite time.