2025 · Paper 1 · Physics
Question 16
The printed question, the official key, and each model’s JSON answer plus the reasoning it wrote.
Q16
Official C
Model answers
Claude Fable 5.1
Anthropic
C
Claude Fable 5.1 reasoning
P: E ∝ Z² — hydrogen-like atom energy levels E_n = -13.6 Z²/n² eV, so radiation from electronic transitions ∝ Z² → (5). Q: E ∝ (Z−1)² — Moseley's law for characteristic X-rays (K_α): √ν ∝ (Z−1) → (1). R: E ∝ Z(Z−1) — Coulomb (electrostatic) term in nuclear binding energy, proportional to number of proton pairs Z(Z−1)/2 → (2). S: practically independent of Z — average binding energy per nucleon (~8 MeV) for A in 30–170 → (4). Match: P→5, Q→1, R→2, S→4, which is option (C).
GPT 6 Astra
OpenAI
C
GPT 6 Astra reasoning
No written reasoning was returned for this item.
GPT 5.6 Luna
OpenAI
C
GPT 5.6 Luna reasoning
No written reasoning was returned for this item.