What substance is obtained as a residue when wood is burned in a limited supply of air?

Solar cells are used to provide the electric current to charge the batteries of a car driven by an electric motor. Describe the energy changes which take place.

What difference would you expect in the charging of car battries

(i) in bright sunlight

(ii) on a cloudy day

(iii) at night?

Name one source of energy which is not derived from solar energy directly or indirectly.

What name is given to the heat energy obtained from hot rocks inside the earth?