When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas is

Options

A. `2/5`
B. `3/5`
C. `3/7`
D. `5/7`

Answer

D

Explanation

Fraction of supplied energy which increase the internal energy is given by
`f = (Delta U)/((Delta Q)_(P)) = ((Delta Q)_V)/((DeltaQ)_P) = (muC_v Delta T)/(mu C_P Delta T) = 1/(gamma)`
For diatomic gas `gamma = 7/5 implies f = 5/7`.