One mole of oxygen undergoes a cyclic process in which volume of the gas change 10 times within the cycle, as shown in the figure. Process: AB and CD are adiabatic. Find the efficiency of the process, in percent. Take (10)0.4 =2.5.

n=1,γ=75⇒ γ−1=25 QAB=QCD=0Let TA=T1 and TD=T2 with T2>T1For the process AB, we have    TVγ−1= constant ⇒TV25= constant ⇒TA10V025=TBV025⇒TB=T1(10)0.4≈2.5T1Similarly, TC=2.5T2Now, QBC=CVΔT⇒QBC=52RTC−TB=(6.25R)T2−T1 and      QDA=−2.5RT2−T1So, Wnet =Qnet =3.75RT2−T1     {∵ΔU=0}⇒ η=Wnet  heat absorbed ×100=3.756.25×100=60%