The nuclear fuel in the sun is:

Why is the use of wood as a fuel not advised although forests can be replenished?

Where are solar cells used?

$(a)$ Why is the solar cooker box covered with a plane glass plate?
$(b)$ Why is energy of water flowing in a river considered to be an indirect form of solar energy?
$(c)$ How is the fission of ${}^{235}U$ nucleus brought about?

What is the role of a plane mirror and a glass sheet in a solar cooker?

Give two advantages of smokeless chulhas over traditional chulhas.