Question

The ultimate source of energy for the earth is
A) Wind energy
B) Hydel energy
C) Chemical energy
D) Solar energy

Answer 1

Hint: The ultimate source of energy is the one which is practically the source for all the earth’s energy. Energy can be grouped into two types based on their renewability− renewable and non-renewable. It is also known as non-conventional and conventional energy respectively.

Complete explanation
Option A Wind energy: Wind energy is the energy derived from wind that converts mechanical to electrical energy. Wind energy is obtained through windmills or wind turbines. It is one of the renewable energies. But this is not the main source of energy.
Option A is not correct.
Option B Hydel energy: Hydel energy also known as hydropower is electrical energy generated by the movement of water. It is also one of the sources of renewable energy but does not contribute more in producing energy. Hence, hydel energy is not the ultimate source of energy.
Option B is not correct.
Option C Chemical energy: Chemical energy is the energy produced from chemical reactions in the form of heat or light. Chemical energy is an example of non-renewable energy. Therefore, it is not considered as an ultimate source of energy.
Option C is not correct.
Option D Solar energy: Sun is the ultimate source of energy for the earth. In the form of solar energy it is converted to light, heat as well as mechanical and electrical energy. Solar energy is a renewable energy resource.
So, option D is correct.

Therefore, Option D is the correct answer.

Note:
Solar energy is considered as the ultimate source of energy because all the energies are derived from it directly or indirectly. For instance, plants convert solar energy into chemical energy for their food. Other animals are dependent on plants for their food and use the chemical energy to maintain homeostasis.