short note on solar energy

Solar energy: The energy emitted by the sun in the form of heat and light (i.e. radiation) is known as solar energy. The sun is the ultimate source of all forms of energy available on the earth. This can be illustrated as follows:

Solar energy heats up the surface of the earth and the air around it. The hot air rises up and the cold air from the surrounding rushes to occupy its space. This makes the air to move. Moving air is known as wind and possesses kinetic energy. Green leaves of plants make their food using sunlight (i.e. sun’s energy) by the process of photosynthesis. The energy stored in the food is known as chemical energy. The food eaten by man or animal provides him the muscular energy. This muscular energy is used to do work. In other words, muscular energy is converted into mechanical energy. The solar energy evaporates the water oceans, rivers, lakes and ponds. The evaporated water forms cloud (having both kinetic energy and potential energy). These clouds on cooling give rain. The rain water flows through rivers and has kinetic energy. The kinetic energy of flowing water rotates the turbine of a generator and produces electricity. Thus, hydro electric energy is also derived from the solar energy. Even the energy of fossil fuels like coal, petroleum and natural gas also comes from the solar energy. Due to high temperature and pressure, the bio-mass of dead animals and plant was converted into the fossil fuel like coal, petroleum and natural gas. These fuels store chemical energy which is converted into heat energy when the fuel burns. This heat energy can be converted into mechanical energy with the help of heat engines.

Thus, we conclude that all forms of energy are derived from a single source –the sun.                                   

 The sun contains mainly light elements like hydrogen and helium. When the atoms of these elements fuse together at extremely high temperature in the interior of the sun, a large amount of energy is radiated in the form of heat. All the plants of solar system receive the energy emitted by the sun. The energy is emitted by the sun in the form of radiation. These radiations are visible rays, infra-red rays (i.e. heat radiation), ultraviolet radiation, gamma rays, x-rays, and radio waves. It may be noted that only some fraction of the total energy emitted by the sun reach the surface of the earth.