Answer: surroundings.
- A surroundings
- B absolute zero
- C boiling point
- D melting point
Correct answer: A. surroundings
Explanation: The rate of cooling is proportional to the excess temperature over the surroundings.
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.