Question

A pendulum having a period of oscillation of $2$ seconds is taken on a planet where g is four times that on the earth. The period of the pendulum would be

• A. $2s$
• B. $1s$
• C. $4s$
• D. $2\sqrt{2}$ s

Answer 1

Answer: (B)

$1s$

As time period of pendulum is,

$T=2\pi \sqrt{\frac{l}{g_{eff}}}$

where, $g_{eff}$ is the effective gravity.

So, $2=2\pi \sqrt{\frac{l}{g}}\left(onearth\right)T=2\pi \sqrt{\frac{l}{4g}}\left(onotherplanet\right)$

On dividing both,

$\frac{2}{T}=2T=1s$