Q9 of 53 Page 1

(a) List any two characteristics of a good fuel.

(b) What are non-renewable resources of energy?


Give two examples of such resources.

(a) The Characteristics of a good fuel are:


(i) A good fuel is require to have a high calorific value.


(ii) It should not create any kind of pollution and shouldn’t burn without emission of any smoke or poisonous gases.


(b) Non-renewable sources are those sources which once finished cannot be renewed again for millions of years. These are limited in amount and take millions of years to renew. The examples of non-renewable sources of energy are:


Fossil fuels and nuclear fuel.


More from this chapter

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7

(a) What is meant by the dispersion of white light? Draw a diagram to show dispersion of white light by the glass prism.

(b) Explain why the planets do not twinkle but the star twinkle.

 8

Define homologous and analogous organs.

Classify the following as homologous or analogous organs:


(i) Wings of an insect and wings of bat.


(ii) Forelimbs of a man and forelimbs of a frog.

 10

Explain how equal genetic contribution of male and female parents is ensured in the progeny.

 11

Explain the terms:

(i) Speciation


(ii) Natural selection