2025 · Paper 2 · Physics
Question 8
The printed question, the official key, and each model’s JSON answer plus the reasoning it wrote.
PhysicsPaper 2Multi correct
Q08
Official A, B, C
Model answers
Claude Fable 5.1
Anthropic
Correct4 / 4
A, B, C
Claude Fable 5.1 reasoning
Carnot engine: η = 0.4, T_H = 1000 K, Q_H = 150 J. - Work W = ηQ_H = 0.4 × 150 = 60 J → (A) correct. - η = 1 − T_C/T_H ⇒ T_C = 1000(1 − 0.4) = 600 K → (B) correct. Heat pump: COP = 10 = Q_H'/W ⇒ Q_H' = 10 × 60 = 600 J → (D) says 540 J, incorrect. Cold reservoir of heat pump: COP (Carnot heat pump) = T_H'/(T_H' − T_C') = 10 ⇒ 300/(300 − T_C') = 10 ⇒ 300 − T_C' = 30 ⇒ T_C' = 270 K → (C) correct.
GPT 6 Astra
OpenAI
Correct4 / 4
A, B, C
GPT 6 Astra reasoning
No written reasoning was returned for this item.
GPT 5.6 Luna
OpenAI
Correct4 / 4
A, B, C
GPT 5.6 Luna reasoning
No written reasoning was returned for this item.