Question

On placing an inverted tumbler over a burning candle, the
flame extinguishes after some time. This is because of nonavailability
of
(a) oxygen (c) carbon dioxide
(b) water vapours (d) wax


NCERT Class VIII
Science - Exemplar Problems

Chapter 6. Combustion and Flame

Answer 1

[a]oxygen.................is the answer

Answer 2

On placing an inverted tumbler over a burning candle, the flame extinguishes after some time. This is because of nonavailability of oxygen.

Explanation:

A tumbler contains air. We know that air is a mixture of several gases including oxygen. Fire needs oxygen to burn. If we cut off the supply of oxygen, the fire will be extinguished. This is the technology behind fire extinguishers.

Similarly, when we invert a tumbler over a burning candle, the candle will continue to burn for some time. This is because the air inside the tumbler will supply oxygen for the fire to burn. When this supply of oxygen is used up, there is no fresh supply of oxygen. So the flame will be put off when the oxygen supply is over.