Helium gas goes through a cycle ABCDA (consisting of two isochoric and two isobaric lines) as shown in figure.

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Helium gas goes through a cycle ABCDA (consisting of two isochoric and two isobaric lines) as shown in figure. The pressure and volume at A are P_0, V_0 and at C are 2P_0, 2V_0 . Efficiency of this cycle is nearly: ![image](https://pub-7faa453bd1ec4bf0a04cc031c6f058de.r2.dev/images/83012df1-3f33-480

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Work done W = Area of rectangle = (2P_0 - P_0)(2V_0 - V_0) = P_0 V_0 .Heat is absorbed during processes AB ( V=V_0, P_0 → 2P_0 ) and BC ( P=2P_0, V_0 → 2V_0 ).For monoatomic gas (Helium), C_v = 3/2R and C_p = 5/2R . Q_AB = n C_v T = 3/2 V_0 (2P_0 - P_0) = 3/2 P_0 V_0 . Q_BC = n C_p T = 5/2 (2P_0) (2V_0 - V_0) = 5 P_0 V_0 .Total heat absorbed Q_in = 3/2 P_0 V_0 + 5 P_0 V_0 = 13/2 P_0 V_0 = 6.5 P_0 V_0 .Efficiency = W/Q_in = P_0 V_0/6.5 P_0 V_0 = 1/6.5 ≈ 0.1538 .In percentage, ≈ 15.4\% .

Helium gas goes through a cycle $A BC D A$ (consisting of two isochoric and two isobaric lines) as shown in figure. The pressure and volume at $A$ are $P_{0}, V_{0}$ and at $C$ are $2 P_{0}, 2 V_{0}$ . Efficiency of this cycle is nearly:

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Helium gas goes through a cycle ABCDA (consisting of two isochoric and two isobaric lines) as shown in figure. The pressure and volume at A are P0​,V0​ and at C are 2P0​,2V0​. Efficiency of this cycle is nearly: