Question

A block of wood is floating in water at $0^{\circ }$C. The temperature of water only is slowly raised from $0^{\circ }$C to ${10}^{\circ }$C. With the rise in temperature of the water the volume of block $V$ above water level will be

• A. increase
• B. decrease
• C. first increase and then decrease
• D. first decrease and then increase

Answer 1

Answer: (B)

decrease

Hot water is less dense than cold.

So, less denser means it require more amount of water to equate its mass with woods mass as per Archimedes principal.

Wood will remove or replace same weight of water as that of wood.

So, when density lowers of water higher amount of water replaces it makes the wood to take more volume inside water.

Thus, volume $V$ of wood outside water decreases.