A hollow sphere filled with water through a small body in it is then hung by a long thread and made to oscillation As the water slowly force end of the hole at the bottom the period of oscillation will

Options

A. continuosly decrease
B. continuosly increase
C. first decreases and then increases to original value
D. first increases and then decrease to original value

Answer

D

Explanation

The given system is like a simple pendulum whose effective length `(i)` equal to the distance between the `CG` of point of suspnded and `CG` (orther of gravity) of the hanging body
When water slowly force system the `CG` of the sphere is toward and hence `1` increases which in the furm increase time period (as`T prop sqrt(1)`).
Aftersome time ewight of mass left in sphere vbecomes less then the weigth of sphere itself i.e. decreases and hence `T` increases
Finaly when the sphere becomes ample the resulting `CG` is the `CG` of sphere i.e. length becomes equal to the original length and hence the time period becomes equal in the same value as shown as when it was half of water