Question

A clock purchased in \[1942\] loses $1$ min in $1$ day. Its time period must have become:
A) Extremely small
B) Extremely large
C) Shorter
D) Longer

Answer 1

Hint: Whenever a clock is running slower than its normal speed, it is said that the clock is losing time. An ideal clock should lose $12$ hours, to give accurate time. But if a clock is running faster than its normal speed, it is said that the clock has gained time. An ideal clock should gain $12$ hours, to give accurate time.

Complete solution:
It is already clear that the clock will lose time if it runs slow. So, this means that the time period of the clock must be longer than $24$ hours. This is why it is taking longer than actual. Also the length of the pendulum clock changes with change in the temperature. If the temperature increases, then the length of the rod will increase as it will expand. So the time period of the clock will increase and the clock will lose time.
If the clock is purchased in $1942$ and loses $1$min in $1$ day, then its time period must have become longer.

Option D is the right answer.

Note: It is important to remember that the length of a pendulum increases with temperature. The length of the pendulum changes due to linear expansion. Linear expansion means the change in one dimension that means length of the object due to the heat of the atmosphere. Due to this heat the particles of the object gain energy and start moving fast and the volume of the object increases. This is also known as thermal expansion of the object.