Question

The figure shows air-filled bulbs connected by a V-tube partly filled with alcohol. What happens to the levels of alcohol in the limbs X and Y when an electric bulb placed midway between the bulbs is lighted ?

• A. the level of alcohol falls in both limbs.
• B. the level of alcohol in the limb X rises while in that in limb Y falls.
• C. the level of alcohol in limb X falls while that in limb Y rises.
• D. there is no change in the levels of alcohol in the two limbs.

Answer 1

Answer: (C)

the level of alcohol in limb X falls while that in limb Y rises.

Black colour being a better absorber of heat, bulb X gets more heated due to heat rediated by the electric bulb resulting in the expansion of air inside it. The expanded air requires more space and so pushes the alcohol towards limb Y.