According to the law of equipartition of energy, the number of vibrational modes of a polyatomic gas of constant $$\gamma=\frac{C_p}{C_v}$$ is ($$C_P$$ where $$C_V$$ are the specific heat capacities of the gas at constant pressure and constant volume, respectively):

A thermodynamic system is taken through the cycle $$abcda$$. The work done by the gas along the path $$b c$$ is:

The following graph represents the $$T$$-$$V$$ curves of an ideal gas (where $$T$$ is the temperature and $$V$$ the volume) at three pressures $$P_1, P_2$$ and $$P_3$$ compared with those of Charles's law represented as dotted lines.

Then the correct relation is :

For the given cycle, the work done during isobaric process is: