Question

The length of the simple pendulum which ticks seconds is:

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

Answer 1

Answer: (B)

$1$m

The time period of a simple pendulum is
$T=2\pi \sqrt{\frac{L}{g}}$
where L is the length of the pendulum.
or $L=\frac{g{T}^2}{4{\pi }^2}$
The time period of the simple pendulum which ticks seconds is $2$s.
$\therefore T=2s$
Substituting in (i), we get

$L=\frac{\left(9.8m{s}^{-2}\right)(2s{)}^2}{4\times (3.14{)}^2}=1m$