Answer: 2 mm.
- A 0.2 mm
- B 2 mm
- C 20 mm
- D 1 mm
Correct answer: B. 2 mm
Explanation: ΔL = LαΔT = 1·2×10⁻⁵·100 = 2×10⁻³ m = 2 mm.
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.