A pendulum has a period `T` for small oscillations. An obstacle is placed directly beneath the pivot, so that only the lowest one - quarter of the string can follow the pendulum bob when it swings to the left of its resting position. The pendulum is released from rest at a certain point. How long will it take to return to that point again ? In answering this question, you may assume that the angle between the moving string and the vertical stays small throughout the motion.

Options

A. T
B. `T//2`
C. `3T//2`
D. `3T//4`

Answer

D

Explanation

`T=2pisqrt((I)/(g))` and `T=2pisqrt((I)/(4g))=(T)/(2)` Rightarrow Required time =`(T)/(2)+(T')/(2)=(3T)/(4)`