List conditions under which combustion can take place.
Burning of wood and coal causes __________ of air.
A liquid fuel, used in homes is __________
Fuel must be heated to its __________ before it starts burning.
Fire produced by oil cannot be controlled by ___________ .
1 of 20
A goldsmith uses the outer zone (non-luminous zone) of candle flame to melt gold and silver because it is hottest zone and has more temperature.