Question

The length of a second?s pendulum at the surface of earth is 1 m. The length of second?s pendulum at the surface of moon where g is 1/6th that at earth?s surface is

• A. 1/6 m
• B. 6 m
• C. 1/36 m
• D. 36 m

Answer 1

Answer: (A)

1/6 m

Answer 2

$T = 2\pi\sqrt{\frac{\ell}{g}}\,;\,2=2\pi\sqrt{\frac{\ell}{g}}=2\pi\sqrt{\frac{\ell'}{\left(g/6\right)}}$
Time period will remain constant on moon. Then, $\ell'$ = $\ell$/6 = 1/6 m