Compare LPG and wood as fuels.

3

(a)

Give reasons.
(a) Water is not used to control fires involving electrical equipments.
(b) LPG is a better domestic fuel than wood.
(c) Paper by itself catches fire easily, whereas a piece of paper wrapped around an aluminium pipe does not.

3

(a)

Name the unit in which the calorific value of a fuel is expressed.

3

(a)

Explain how CO₂ is able to control fires.

3

(a)

Can the process of rusting be called combustion? Discuss.

3

(a)

Abida and Ramesh were doing an experiment in which water was to be heated in a beaker. Abida kept the beaker near the wick in the yellow part of the candle flame. Ramesh kept the beaker in the outermost part of the flame. Whose water will get heated in a shorter time?

3

(a)

You are provided with three watch glasses containing milk, petrol and mustard oil respectively. Suppose you bring a burning candle near these materials one by one, which material(s) will catch fire instantly and why?

3

(a)

What should be done to control fire due to oil?

3

(a)

Why a matchstick can burn a splinter of wood directly but cannot burn a log of wood directly? How can we burn a log of wood?

3

(a)

A matchstick does not catch fire on its own. But when it is rubbed, it starts burning. Why?

3

(a)

Give the name of two energy sources that you would consider to be exhaustible. Give reasons for your choices.

3

(a)

Write an experiment to show that air is necessary for burning of a candle.

3

(a)

Explain briefly different types of combustion.

3

(a)

How does a match stick burn? Explain its process.

3

(a)

Uneducated and careless people are not aware of saving fossils, such as, coal and petroleum. Discuss some points how you can make them aware regarding this.

3

(a)