0In a cyclic process,the system starts and returns to the same thermodynanic state.The total internal - energy change in any cyclic process is zero.
The net work involved is the enclosed area on the P - V diagram. If the cycle goes clockwise,the system does work.
Lets try an example:
According to the thermodynamics equation, change in the internal energy of the system = (heat added to the system) - (work done by the system).
