A gas takes part in two processes in which it is heated from the same initial state 1 to the same final temperature. The processes are shown on the P-V diagram by the straight line 1-2 and 1-3. 2 and 3 are the points on the same isothermal curve. Q₁ and Q₂ are the heat transfer along the two processes. Then in which case will the heat transfer be more. Which of the following gives the correct final result?

Question

G1 Physics · Accepted Answer

Use the first law Q=ΔU+W (W by the gas), ΔU=nCᵥΔT for an ideal gas, and the appropriate process relation. For Carnot devices, let T₁ be the cold-reservoir temperature and T₂ be the hot-reservoir temperature; η=1-T₁/T₂ and COP=T₁/(T₂-T₁). Evaluating the given data/statements gives Q₁<Q₂. Therefore the correct answer is A.