Question

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

Answer 1

Answer: (C)

2 T

Answer 2

When lift is at rest, $T = 2 \pi \sqrt { l / g }$

If acceleration becomes g/4 then

$T ^ { \prime } = 2 \pi \sqrt { \frac { l } { g / 4 } } = 2 \pi \sqrt { \frac { 4 l } { g } } = 2 \times T$