Heat energy absorbed by a system going through the cyclic process shown in the figure is

A polyatomic gas with $n$ degrees of freedom has a mean kinetic energy per molecule given by (if $N$ is Avogadro's number )

The absorption coefficient value of a perfect black body is

A certain volume of a gas at 300 K expands adiabatically until its volume is doubled. The resultant fall in temperature of the gas is nearly (The ratio of the specific heats of the gas $=1.5$ )