Question

Which source of energy is not ultimately derived from the sun's energy?

• A. Bio-mass
• B. Geothermal energy
• C. Wind energy
• D. Nuclear energy

Answer 1

Answer: (B), (D)

Nuclear energy

Explanation for the correct answer:

In case of option B.

1. Unlike other renewable energy sources, geothermal systems are said to be “baseload.”
2. This means they can work in the summer or winter.
3. And are not dependent on changing factors such as the presence of wind or sun.
4. Thus, option B is also correct.

In case of option D.

1. The energy that is required for combining two nuclei is provided by the fission reactions.
2. There is no sunlight involved in this reaction. So, it is obvious that there is no ultimate derivation of energy from the sun.
3. It is a kind of non-renewable form of energy because nuclear substances are limited and hence we will run out of them one day.
4. All the other sources of energy are directly or indirectly derived from the ultimate source of energy.

Explanation for the incorrect answers:

In case of option A.

1. Biomass contains stored chemical energy, which is derived from the sun.
2. Plants produce biomass through photosynthesis, which requires sunlight.
3. They can be burned directly for heat or They can be converted to renewable liquid and gaseous fuels through many processes.
4. Thus, option A is incorrect.

In case of option C.

1. The sun powers the wind by heating some parts of the earth more than others.
2. The wind is the movement of air.
3. The sun heats the air, and the warm air rises from its level.
4. This warm air makes the cooler air from the other areas come in to replace it.
5. Thus, option C is also incorrect.

Thus, the correct options are options A and D.