Q.4 Give reasons for the following a) Fires caused by electrical equipment's cannot be extinguished with water. b) Hydrogen is not used as fuel for domestic purposes c) goldsmith uses outermost zone of candle flame to melt gold and silver. d) It is easy to burn dry leaves as compared to fresh leaves e) flames always point upwards. f) Blanket is wrapped around a person whose clothes have caught fire.
Answers
Explanation:
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) Since water is a good conductor of ele
ctricity, it may result in electric shocks to the person trying to extinguish fire.
(b) LPG is better domestic fuel than wood because it does not produce gases, nor does it leave any residue behind. Moreover, it has more calorific value than wood.
(c) As its ignition temperature is low, the paper by itself catches fire easily. But a piece of paper wrapped around an aluminium pipe does not catch fire easily, as the heat being given gets absorbed by the aluminium pipe and the piece of paper does not get its ignition temperature.