One mole of an ideal gas goes from an initial state A to final state B via two processes : It first undergoes isothermal expansion from volume V to 3V and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram representing the two process is

A mass of diatomic gas $$(\gamma = 1.4)$$ at a pressure of 2 atmospheres is compressed adiabatically so that its temperature rises from 27^oC to 927^oC. The pressure of the gas in the final state is

During an isothermal expansion, a confined ideal gas does $$-$$ 150 J of work against its surroundings. This implies that

When 1 kg of ice at 0^oC melts to water at 0^oC, the resulting change in its entropy, taking latent heat of ice to be 80 cal/^oC, is