Q: 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
(a) 2/5
(b) 3/5
(c) 3/5
(d)5/7
Ans: (d)
Sol: Fraction , $\large f = \frac{\Delta U}{\Delta Q} $
$\large f = \frac{n C_V \Delta T}{n C_P \Delta T} $
$\large f = \frac{ C_V }{C_P} = \frac{1}{\gamma} $
$\large f = \frac{5}{7} $