Q. Why is the candle flame more luminous than that from an LPG burner?
Ans. It’s the oxygen which plays the key role here. Actually, oxygen is the supporter of combustion. In case of a burning candle, due to the insufficient availability of oxygen, some carbon particles are left unburnt that are heated up and get illuminated to give a bright yellow light whereas burning of LPG in a burner is supplied with enough oxygen so that no unburnt carbon particles are left which may glow up to make the fire luminous.