Question

In case of an incense stick or an agrbati the smoke at the lighted end of stick moves in upward direction it is because
A. the cool air below the lighted end moves to take the place of hot air above the lighted end
B. the air at the hot ends is more dense
C. it is natural for the smoke to move up
D. the smoke is repelled by the gravity of earth

Answer 1

Correct Answer - a
In case of an incense stick the air at the lighted end is hot and hence volume increase and density decrease so it rises up (moves up)
the air at the hot end is at a higher temperature so its density is less and this lesser dense air rises up and more dense air occupies this place so it is due to convection of gases