Question

Due to thermal expansion with rise in temperature
(a) Metalic scale reading becomes lesse than true value
(b) Pendulum clock goes fast
(c) A flowing body sinks a little increases
(d) The weight of a body in a liquid increases

• A. only (a) is correct
• B. (a)&(b) are correct
• C. (a),(b) & (d) are correct
• D. (a),(c) & (d) are correct

Answer 1

Answer: (D)

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, $T=2\pi \sqrt{\frac{T}{g}}$. On heating, since 1 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.