JEE Advanced · 2018 · 20 May 2018 · Paper 1 · Heat & Thermodynamics

From the V-T diagram: Process II is isothermal (constant T) with increasing V, so $\Delta U=0$ and $Q=W>0$ (gas absorbs heat) — correct. Process IV is isothermal with decreasing V, so $W<0$ and $Q<0$ (gas releases heat) — correct. Processes I and III are not straight lines through the origin in a V-T diagram, so they are not isobaric (which would require $V\propto T$) — correct. Process I is not isochoric (constant volume) — incorrect.