GATE 2026 PI – Question 29

General Engineering · Thermal and Fluids Engineering · 1 mark · Multiple select

Which ONE OR MORE processes of the Carnot cycle shown are isentropic? Figure is not to scale.

1–2
2–3
3–4
4–1

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Show answer and explanation

Correct answer: (B) 2–3; (D) 4–1

Explanation

A reversible Carnot cycle has two isothermal processes and two reversible adiabatic processes. Reversible adiabatic processes have no entropy change. In the shown P–V cycle these are the steeper connecting paths **2–3 and 4–1: B,D**.

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