P-V Diagrams & Cyclic Processes question from MHT CET 2026 (14 May, Shift 2)

Answer: (a)

1. Graph (a): curve falling gently, $PV =$ constant: isothermal.
2. Graph (b): horizontal line, constant $P$: isobaric.
3. Graph (c): vertical line, constant $V$: isochoric.
4. Graph (d): steeper curve ($PV^{\gamma} =$ constant, $\gamma > 1$): adiabatic.
5. Order isothermal, isobaric, isochoric, adiabatic is a, b, c, d, so the answer is (a).