A block of wood is floating on water at `0^(@)C` with a certain volume `V` above water level. The temperature of water is slowly raised to `20^(@)C` . How does the volume `V` change with the rise of temperature ?

Options

A. remain unchanged
B. decrease continuously
C. decreases till `4^(@)C` and then incresase
D. increases till `4^(@)C` and then decresase

Answer

D

Explanation

`V` : volume outside the water
`V'` : volume inside the water
In case of floatation
`W` : constant
From `0^(@)` to `4^(@)C` , density of water decreases i.e., `V` increases
From `4^(@)C` to `20^(@)C` , density of water decreases `V'` increases i.e., `V` decreases