In a cyclic process,ΔU=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 anticlock wise ∴ΔW=− Area of rectangle ABCD=−P(2V)=−2PV According to first law of thermodynamics ΔQ=ΔU+ΔW or ΔQ=ΔW (As ΔU=0) i.e., heat supplied to the system is equal to the work done So heat absorbed, ΔQ=ΔW=−2PV ∴ Heat rejected by the gas = 2PV