Q.Energy from various sources is considered to have been derived from the sun. Do you agree? Justify your answer.
Ans. Yes, sun is the ultimate source of energy directly or indirectly, all the forms of energy derived from solar energy.
(i) Non-renewable sources of energy Fossil fuels like coal, petroleum and natural gas are formed due to burial of large plants and ancient creatures whose ultimate source of energy is sun.
(ii) Renewable sources of energy They are indirectly derived from solar energy such as:
- Energy from flowing water Clouds are formed when water in lakes, rivers, seas etc., evaporates due to solar energy. They bring rainfall and snow fall.
- Wind energy Wind energy arises due to uneven heating of the earth’s surface by the Sun rays at two different adjoining places. Due to this, wind possesses kinetic energy.
- Bio-energy Plants in the process of photosynthesis convert the solar energy into food (chemical energy). This food is consumed by animals.
- Wave energy The waves are generated by strong winds (due to solar energy) blowing across the sea.
- Ocean thermal energy Sun is responsible for the temperature difference between the water at the surface and water at depth in seas and oceans.
(iii) Solar beating devices They derive their energy directly from solar energy and convert it into other usable forms of energy.