Question

Due to the thermal expansion, with rise in temperature

• A. Metallic scale reading becomes lesser than true value ($\alpha$ of the metal is greater than $\alpha$ of the object)
• B. Pendulum clock becomes slower
• C. A floating body sinks little more (assuming temperature of liquid remains unchanged)
• D. The apparent weight of a body in a liquid may decrease (assuming temperature of liquid remains unchanged)

Answer 1

Answer: (A), (B), (D)

The correct options are
A Metallic scale reading becomes lesser than true value ($\alpha$ of the metal is greater than $\alpha$ of the object)
B Pendulum clock becomes slower
D The apparent weight of a body in a liquid may decrease (assuming temperature of liquid remains unchanged)

On increasing temperature, the distance between scales of metallic scale will increase and hence the measured value will be lower than actual value.

For pendulum clock, $T=2\pi \sqrt{\frac{l}{g}}$. On heating, since $l$ increases, time period will increase and clock will become slower.

Due to heating, density decreases and hence a floating body sinks a little less in liquid.

Since due to thermal expansion, volume of the body will increase and hence the volume of water displaced by the body will also increase. Thus, force of buoyancy on the body will also increase and hence its apparent weight will decrease.

Answer is A, B and D.