Question

Sun produces heat and light by:

Answer 1

Hint: Try to identify the composition of the sun. Composition includes elements that exist in gaseous as well as in molten state. Sun is a star. So, the reason for any star producing heat and light will be valid for the sun. Write the reaction of elements present in the sun to understand the reason for emission of heat and light.

Complete step-by-step answer:
The Sun is the star present at the centre of the solar system. It is a nearly perfect sphere of hot plasma, heated to produce incandescence by nuclear fusion reactions in its core. The energy is emitted mainly in the form of radiations of visible light as well as infrared light.
It is an important source of energy for life on earth. The sun is composed of primarily hydrogen and helium elements. The elements account for 74.9% and 23.8% respectively.
Since the formation of the Sun, the main process taking place is nuclear fusion. Fusion involves fusing hydrogen molecules to form helium. This process releases a lot of heat.
We can conclude that the main reason for the Sun producing heat and light is nuclear reactions.

Therefore, the correct answer is option (C).

Note: The nuclear fusion of hydrogen molecules to form helium takes place in the core of the sun only and not in the whole volume of the sun. The core at present is the inner 20-25% of the sun's radius only.