Thermodynamic Processes question from MHT CET 2026 (15 May, Shift 2)

Answer: (c)

1. Molar heat capacity $C = \dfrac{\Delta Q}{n\,\Delta T}$.
2. Adiabatic: $\Delta Q = 0$ while $\Delta T \neq 0$, so $C = 0$.
3. Work done by the gas equals the decrease (not increase) in internal energy, and $U$ rises with $T$ for an ideal gas, so (b) and (d) are false.
4. So the answer is (c) the molar heat capacity is zero.