If one kilogram water at `100^(@)C` is vapourised in open atmosphere. The correct statement is

Options

A. increase in internal energy is equal to L (L is latent heat of vaporisation for 1 Kg)
B. increase in internal energy is zero
C. increase in internal energy is less than L
D. none of the above

Answer

C

Explanation

Heat of vaporisatioin in given by,
Q = mL=L (`therefore` m=1kg)
`DeltaU` = Q-W=L-W
i.e, `DeltaUltL`