CBSE Class 10 Answered

We use many different forms of energy here on earth, but here's the thing: almost all of them originate with the sun, not just light and heat (thermal) energy. The law of conservation of energy says that energy can't be created or destroyed, but can change its form. And that's what happens with energy from the sun - it changes into lots of different forms:
1. Plants convert light energy from the sun into chemical energy (food) by the process of photosynthesis. Animals eat plants and use that same chemical energy for all their activities.
2. Heat energy from the sun causes changing weather patterns that produce wind. Wind turbines then convert wind power into electrical energy.
3. Hydroelectricity is electrical energy produced from moving water, and water flows because heat energy from the sun causes evaporation that keeps water moving through the water cycle.
4. Right now, much human activity uses energy from fossil fuels such as coal, oil, and natural gas. These energy sources are created over very long periods of time from decayed and fossilized living matter (animals and plants), and the energy in that living matter originally came from the sun through photosynthesis.