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 3 V and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram representing the two processes is :
In isothermal expansion T = constant ⇒ PV = constant ⇒ graph is rectangular hyperbola.
At constant pressure P = constant