A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is

A thermodynamic system is taken through the cycle ABCD as shown in fig

1.	A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is
Answer» 2PV 4PV `(1)/(2)PV` PV Solution :In a cyclic process, `Delta U = 0`. In a cyclic process work done is equal to the area under the cycle and is positive if the cycle is CLOCKWISE and negative if anticlockwise. `:. Delta W = - "Area of REACTANGLE ABCD " = - P(2V) = -2PV` ACCORDING to first law of thermodynamics `Delta Q = Delta U + Delta W` or `Delta Q = Delta W` (As `Delta U = 0`) i.e., heat supplied to the system is equal to the work done So heat ABSORBED, `DETA Q = Delta W = -2PV` `:.` Heat rejected by the gas= 2PV