Although coal and petroleum are produced by degradation of biomass, yet we need to conserve them. Why? Mention two reasons.

Why are the coal, petroleum and natural gas called fossil fuels?

Coal and petroleum are which type of resources? Give reason.

Which fossil fuel is conserved :

(a) when we save on electricity?

(b) when we use bicycle for covering short distances instead of a motorbike ?

Choose one term from the following which include all others :

coal, natural gas, fossil fuels, petroleum

There are two important fuels A and B both of which are extracted from deep inside the earth. Fuel A is a thick, dark, foul smelling liquid whereas fuel B is a black solid. Combustion of both the fuels produces products, C, D, E and F. The product C makes the rainwater only slightly acidic but it is mainly responsible for causing global warming. The product D is neither acidic nor basic. It is harmless and does not affect the environment in any way. Both E and F attack breathing system of humans and are mainly responsible for causing acid rain. In addition to combustion of fuels A and B, the product F is also formed when lightning occurs in the sky.

(a) What are (i) fuel A, and (ii) fuel B ? (b) Name (i) C (ii) D (iii) E, and (iv) F

(c) What is the process of formation of F during lightning known as ?

(d) Which fuel is supposed to be exhausted sooner : A or B ?

(e) Which fuel is mostly used for generating electricity at thermal power plants ?

Pick the right combination of terms which has no fossil fuel.