Question

What is the length of the simple pendulum which ticks second?

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