SOLAR ENERGY is the radiant energy that we receive from the sun in the form of heat and light. It is an inexhaustible source of energy. Solar Energy is the ultimate source of most of the sources of energy that we use. The wind energy, water energy, energy of fossil fuels and the energy in food are due to solar energy.
SOURCE OF SOLAR ENERGY
The discovery of radioactivity led some scientists to suggest that the energy released during radioactive decay of radioactive materials in the sun, might be the source of solar energy. As the liberation of energy from this is extremely slow, the hypothesis was rejected. Some scientists suggested that the thermonuclear reactions could be the source of solar energy. This could explain the observed radiations from the sun. The most convincing explanation was given by Hans Bethe and C.von Weizsäcker. Bethe suggested that the reaction in which hydrogen nuclei fuse to form helium nuclei is the source of solar energy of the sun. In this process, enormous amount of energy is released.
REACTIONS IN THE SUN
There are two different cycles of processes. One is the proton-proton chain or p-p chain. The other is the Carbon Cycle or CNO cycle (Carbon-Nitrogen-Oxygen) or sometimes Bethe- Weizsäcker-cycle. Proton-Proton chain: The proton–proton chain reaction is one of the fusion reactions in which four Hydrogen nuclei fuse into one Helium nucleus with the release of enormous amount of energy in the form of Gamma rays. Carbon Cycle: Carbon cycle, CNO cycle (Carbon-Nitrogen-Oxygen), or sometimes Bethe-Weizsäcker-cycle, is a fusion reactions by which stars convert hydrogen to helium. The Carbon cycle is a catalytic cycle. In the carbon cycle, the carbon atom acts as a nuclear catalyst.
NATURAL TRANSFORMATION OF SOLAR ENERGY
Many of the useful sources of energy come from the natural transformation of solar energy. They are: * Wind Energy
* Water Energy
* Energy in food