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

Options

A. continuously decrease
B. continuously increase
C. first decrease then increase
D. first increase then decrease

Answer

C

Explanation

The time period of the pendulum
`T=2pisqrt(l//g)`
`impliesTpropsqrtl`
Initially the centre of mass of the sphere is at the centre of the sphere. As the water slowly flows out of the hole at the bottom, the CM of the liquid (hollow sphere) first goes on downward and then upward. Hence, the effective length of the pendulum first increases and then decreases.