Q53. An ideal gas, $\overline { \mathrm { C } } _ { \mathrm { v } } = \frac { 5 } { 2 } \mathrm { R }$, is expanded adiabatically against a constant pressure of 1 atm untill it doubles in volume. If the initial temperature and pressure is 298 K and 5 atm , respectively then the final temperature is\\
$\_\_\_\_$ K (nearest integer). [ $\overline { \mathrm { C } } _ { \mathrm { v } }$ is the molar heat capacity at constant volume]