When unit mass of water boils to become steam at `100^(@)C`, it absorbs Q amount of heat. The densities of water and steam at `100^(@)C` are `rho_(1)` and `rho_(2)` respectively and the atmospheric pressure is `P_(0)`. The increase in internal energy of the water is

Options

A. Q
B. `Q+P_(0)((1)/(rho_(1))-(1)/(rho_(2)))`
C. `Q+P_(0)((1)/(rho_(2))-(1)/(rho_(1)))`
D. `Q-P_(0)((1)/(rho_(1))+(1)/(rho_(2)))`

Answer

B

Explanation

`DeltaU=DeltaQ-W`
`=Q-P_(0)[(1)/P_(2)-(1)/(P_(2))]`
`=Q+P_(0)[(1)/(P_(2))-(1)/(P_(1))]`