question_answer 5)

Give reasons : (a) Water is not used to control fires involving electrical equipment. (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.  

Answer:

(a) Water is a good conductor of electricity. It conducts electricity and may result electric shock.   (b)LPG has more calorific value than wood and LPG produces no pollution. So LPG is a better domestic fuel than wood.   (c)The ignition temperature of paper is less, so it catches fire easily. It does not catch fire when wrapped around aluminium pipe because aluminium absorbs the heat so paper does not attain its ignition temperature.