question_answer

Pendulum clocks generally run fast in winter and slow in summer. Why?

Answer:

                The time period of a simple pendulum is given by \[T=2\pi \sqrt{\frac{l}{g}}\]  i.e., \[T\propto \sqrt{l}.\] In winter, \[l\] decreases with the fall in temperature, so T decreases and clocks run fast. In summer \[l\]increases with the increase in temperature, so T increases and clock runs slow.