Answer: 9/7.
- A 5/3
- B 7/5
- C 9/7
- D 4/3
Correct answer: C. 9/7
Explanation: With f=7 (3 translational + 2 rotational + 2 vibrational), Cv=(7/2)R, Cp=(9/2)R, so γ=Cp/Cv=9/7 ≈ 1.29.
During a phase change (melting or boiling), temperature stays constant while heat is absorbed entirely as latent heat (Q=mL); temperature only rises again once the substance is fully in its new phase.
Concept context
Temperature scales, thermal expansion, calorimetry, and the three modes of heat transfer including radiation laws.