Question

A block is floating in a liquid. ‘f’ is the fraction of its volume immersed in the liquid. Choose the correct options.

• A. If the system is taken to a lift accelerating upwards, ‘f’ will increase
• B. If the system is taken to a place where atmospheric pressure is more, ‘f’ will remain unchanged
• C. If temperature is increased and expansion of only the liquid is considered, ‘f’ will increase
• D. If heat is given to the block only and expansion of block only is considered, ‘f’ will remain constant

Answer 1

Answer: (B), (C)

The correct options are
B If the system is taken to a place where atmospheric pressure is more, ‘f’ will remain unchanged
C If temperature is increased and expansion of only the liquid is considered, ‘f’ will increase

When a body is floating, $mg=V_i\rho g=\text{f}{V}_{total}\rho g$, where $m$ is the mass of the body and $\rho$ is density of the liquid, $V_i$ is volume displaced, f is fraction of total volume immersed.

‘f’ will not depend on atmospheric pressure.

When temperature of the liquid is increased, its density decreases. When the temperature of the body is increased, its mass does not change. So 'f' will increase.

Similarly if expansion of only block is considered, then f will change as mass will be constant and total volume will change.