If a Second's pendulum is moved to a planet where acceleration due to gravity is $4$ times, the length of the second's pendulum on the planet should be made .......... times

A simple pendulum is vibrating in an evacuated chamber, it will oscillate with

The angular amplitude of a simple pendulum is $\theta_0$. The maximum tension in its string will be

Two simple pendulums of length $1\, m$ and $4\, m$ respectively are both given small displacement in the same direction at the same instant. They will be again in phase after the shorter pendulum has completed number of oscillations equal to

The time period of a simple pendulum is $2\, sec$. If its length is increased $4$ times, then its period becomes  ..... $\sec$

Length of a simple pendulum is $l$ and its maximum angular displacement is $\theta$, then its maximum $K.E.$ is