Figure shows a hollow cube of side `'a'` and volume `'V'`. There is a small chamber of volume `V//4` in the cube as shown. The chamber is completely filled by in kg of water. Water leaks through a hole `H` and spreads in the whole cube. Then the work done by gravity in this process assuming that the complete water finally lies at the bottom of the cube is

Options

A. `1/2mg a`
B. `3/8 mg a`
C. `5/8mg a`
D. `1/8mg a`

Answer

C

Explanation

Let `h` be the heigh of water surface.

Then `a^(2)h=axxa/2xxa/2`
`h=a/4`
`CM` gets lowered by
`a-(a/4+a/8)=a(3a)/9=(5a)/8`