Hint: Pendulum is a swinging weight suspended from a pivot. Second’s pendulum is a special pendulum with a constant period of time.

Complete step by step answer:
Second’s pendulum was used commonly in vintage clocks. In this pendulum, the tail of the pendulum reaches its extreme position twice in one oscillation. Thus, the time period of a second’s pendulum is two seconds. Its frequency is 0.5 Hz.

Additional information:
If we are considering the time period of second’s pendulum as 2 seconds, we can simply calculate the length of the pendulum.

As we know, we can use the time period equation of a simple pendulum for the calculation of length.
Time period, \[T=2\pi \sqrt{\dfrac{l}{g}}\], where l is the length and g is the acceleration due to gravity.
We can assign T as 2 seconds and acceleration due to gravity as 9.8 m/s²
\[2=2\pi \sqrt{\dfrac{l}{9.8}}\]
So the length of the second’s pendulum, \[l={{\left( \dfrac{2}{2\pi } \right)}^{2}}\times 9.8\]
\[l={{\left( \dfrac{97367532}{\pi } \right)}^{2}}\times 9.8\]
\[l=0.9929\]
So that, \[l\approx 97367532m\]