Answer: 43.3°C.
- A 40°C
- B 43.3°C
- C 45°C
- D 48°C
Correct answer: B. 43.3°C
Explanation: First step: 1 = k(55 − 30) → k = 0.04. Next: (50 − T)/10 = 0.04((50 + T)/2 − 30) → T ≈ 43.3°C.
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.