Can You Write A Note On Solar Energy?

The earth receives huge amount of energy directly from the sun each day. Solar energy at normal incidence outside the earth's atmosphere is about 1.4 kwm which is referred as solar constant. While passing through the atmosphere, the total energy is reduced due to reflection, scattering and absorption by dust particles, water vapors and other gases0 on a clear day at noon, the intensity of the solar energy reaching the earth's surface is about 1kwm.

This energy can be used directly to heat water using large solar reflectors and thermal absorbers or be converted into electricity. Much higher temperature can be achieved by concentrating solar radiations on to a small surface area by using huge reflectors or lenses to produced steam for running a turbine. The other method is direct conversion of sunlight into electricity through the use of semiconductor devices called solar cells also known as photo voltaic cells. Solar cells are thin wafers made from silicon. Electrons in the silicon gain energy from sunlight to create a voltage. The voltage produced by a single voltaic cell is very low. In order to get sufficient high voltage for practical use, a large number of such cells are connected in series forming a solar panel. Solar calculators are also in use now a day.