A block of wood is floating on the surface of water in a beaker. The beaker is covered with a bell jar and the air is evacuated. What will happen to the block ?

Options

A. Sink a little
B. Rise a little
C. Remain unchanged
D. Sink completely

Answer

C

Explanation

In the first case,
Initially (p-p)A=weight of block
or `[(p_(0)+rho gh_(1))-p_(0)]A=w " or" h_(1)=(w)/(A rho g)`
In the second case,
`p_(2)A=w " or" (rho gh_(2))A=w " or " h_(2)=(w)/(rho Ag)`
From Eqs. (i) and (ii), we see that `h_(1)=h_(2)`