Answer: 2:1.
- A 1:1
- B 1:2
- C 2:1
- D 4:1
Correct answer: C. 2:1
Explanation: Rate of heat conduction H ∝ A (Fouriers law) for the same K, L, ΔT. Since A<sub>rod</sub> = 2×A<sub>rodB</sub>, ratio H<sub>A</sub>:H<sub>B</sub> = 2:1.
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.