A piece of ice (heat capacity=`2100Jkg^-1^@C^-1` and latent heat `=3.36xx10^5Jkg^-1`) of mass m grams is at `-5^@C` at atmospheric pressure. It is given 420J of heat so that the ice starts melting. Finally when the ice-water mixture is in equilibrium, it is found that 1gm of ice has melted. Assuming there is no other heat exchange in the process, the value of m is

Answer

8

Explanation

Using conservation of energy.
`420=(mxx10^(-3))(2100)(5)+(1xx10^(-3))(3.36xx10^(5))`
Solving this equation, we get m = 8 g `therefore` The correct answer is 8.