A cyclic process is shown in p-v diagram and T-S diagram. Which of the following statement(s) is/are true ?
On a p-v diagram a horizontal line is constant pressure and a vertical line is constant volume; on a T-S diagram a vertical line is constant entropy, i.e. a reversible adiabatic process. For a full cycle the internal energy returns to its starting value.
Step 1 — In the p-v diagram 1→2 is horizontal (isobaric) and 3→1 is vertical (isochoric).
Step 2 — In the T-S diagram 2→3 is a vertical line: entropy stays constant while temperature changes, so 2→3 is adiabatic, not isothermal.
Step 3 — The net work is \(W=\oint p\,dV\), the area enclosed by the loop on the p-v diagram; the loop encloses a finite area, so the work is non-zero.
Step 4 — The net heat is \(Q=\oint T\,dS\), the area enclosed by the loop on the T-S diagram, which is also finite. Consistently, for the cycle \(\Delta U=0\;\Rightarrow\;Q=W\).
The statement calling 2→3 isothermal fails because temperature falls along 2→3 on the T-S diagram. The statement on isochoric 3→1 and adiabatic 2→3 holds, as does the non-zero net work and the non-zero net heat absorbed.
3→1: Isochoric, 2→3: adiabatic., Work done by the system in the complete cyclic process is non-zero. and The heat absorbed by the system in the complete cyclic process is non-zero. options are correct.
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