Q. There is a simple pendulum hanging from the ceiling of a lift. When the lift is stand still, the time period of the pendulum is $T$. If the resultant acceleration becomes $g/4$, then the new time period of the pendulum is
A) $0.8\ T$
B) $0.25\ T$
C) $2\ T$
D) $4\ T$
Explanation
(c) When lift is at rest, $T = 2\pi\sqrt{l/g}$
If acceleration becomes $g/4$ then
$T^{'} = 2\pi\sqrt{\frac{l}{g/4}} = 2\pi\sqrt{\frac{4l}{g}} = 2 \times T$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.