Question

The length of the simple pendulum which ticks seconds is

• A. $0.5m$
• B. $1m$
• C. $1.5m$
• D. $2m$

Answer 1

Answer: (B)

The time period of a simple pendulum is
$T=2\pi \sqrt{\frac{L}{g}}$
where $L$ is length of the pendulum
or $L=\frac{g{T}^2}{4{\pi }^2}$ $\dots \left(i\right)$
The time period of the simple pendulum which ticks seconds is $2s$
$\therefore T=2s$
Substituting in (i), we get
$L=\frac{\left(9.8m{s}^{-2}\right){\left(2s\right)}^2}{4\times {\left(3.14\right)}^2}=1m$