CAPF AC 2021 Q22: Science & Technology – Physics
Which one among the following is not a renewable energy source?
- (a) Solar
- (b) Wind
- (c) Nuclear
- (d) Hydroelectric
Answer: (c) Nuclear
Explanation
Renewable and non-renewable energy
How to think: a renewable source is refilled by nature again and again.
A non-renewable source uses a fuel that is limited in the Earth.
Nuclear power needs uranium, which is mined and limited.
| Source | Fuel or input | Type |
|---|---|---|
| Solar | Sunlight | Renewable |
| Wind | Moving air | Renewable |
| Hydroelectric | Flowing water, refilled by rain | Renewable |
| Nuclear | Uranium, thorium (mined minerals) | Non-renewable |
A common confusion: nuclear power is low-carbon, but it is not renewable.
Clean and renewable are two different ideas.
Answer: (c) Nuclear.
Why each option is right or wrong
- (a) Incorrect. Solar energy comes from the Sun and does not run out.
- (b) Incorrect. Wind is replaced continuously by nature.
- (c) CORRECT. Nuclear energy depends on uranium, a limited mined fuel.
- (d) Incorrect. Hydroelectric power uses water that the water cycle refills.
Key point
Renewable: solar, wind, hydro, tidal, geothermal, biomass. Non-renewable: coal, petroleum, natural gas and nuclear (uranium). Nuclear is low-carbon but not renewable.
Remember
Nuclear is clean but not renewable.
Common mistakes
- Treating nuclear as renewable because it does not burn coal or oil.
- Marking hydroelectric as non-renewable because dams are man-made.
- Mixing up clean energy with renewable energy; they are not the same.
Exam tip
Educated guess: ask which option needs a mined fuel. Sun, wind and water are free flows; only nuclear needs uranium.
Sources
- NCERT Class X Science — Sources of Energy
- Ministry of New and Renewable Energy — renewable energy sources (solar, wind, small hydro, bio-energy)