Question

Give reason candle goes off after sometime, when it is covered in jar

Answer 1

A candle goes of after sometime when it is covered with a jar because for combustion to occur, oxygen is needed. The act of keeping of jar cuts the supply of oxygen and the flame extinguishes.
Hope it helps u.

Answer 2

because air is everywhere and it contains gases like carbon dioxide,nitrogen,oxygen etc .And when the candle is covered with a jar the oxygen inside the jar is used by the candle to perform the process of combustion and after it uses all the oxygen in the jar .It goes off as there is no more supply of oxygen.
helpful??