Answer: -273.15°C.
- A 0°C
- B -273.15°C
- C 100°C
- D -100°C
Correct answer: B. -273.15°C
Explanation: Absolute zero, 0 K, corresponds to -273.15°C, the theoretical lowest possible temperature.
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.