A 0.60 kg sample of water and a sample of ice are placed in two compartmetnts A and B separated by a conducting wall, in a thermally insulated container. The rate of heat transfer from the water to the ice through the conducting wall is constant P, until thermal equilibrium is reached. The temperature T of the liquid water and the ice are given in graph as functions of time t. Temperature of the compartments remain homogeneous during whole heat transfer process. Given specific heat of ice `=2100 J//kg-K`, specific heat of water `=4200 J//kg-K`, and latent heat of fusion of ice `=3.3xx10^5 J//kg`.

Options

A. The value of rate P is
B. 42.0 W
C. 36.0 W
D. 21.0 W

Answer

A

Explanation

In 40 min. Temperature of water has water has come down by `40^@C` .
Therefore rate `P=(mSDeltaT)/(t)=(0.60xx4200xx40)/(40xx60)=42W`