Question

The length of a second pendulum $(g=980cm/s^2)$ is nearly _________.

• A. $25$cm
• B. $50$cm
• C. $100$cm
• D. $300$cm

Answer 1

The correct option is C $100$cm

The time period of a second pendulum is 2 seconds.

So its length is given as, $L=g\frac{T^2}{4{\pi }^2}=980\times \frac{4}{4\times {3.14}^2}\approx 100cm$

Option C is correct.