Physics - Heat & Thermo Question with Solution | TestHub

Isobaric: the gas may expand ($W>0$), be compressed ($W<0$) or keep its volume ($W=0$): A$\to$R.

Isothermal: $\Delta T=0$ (P) and $\Delta U=0$ (Q); with $\Delta U=0$ the heat absorbed equals the work done, and the printed key also matches S: B$\to$P,Q,S (kept as printed).

Adiabatic: $Q=0$, so energy exchange is only through work (S) and that work may be positive, negative or zero (R): C$\to$R,S.