Energy is exchanged by which two phase-change processes alone?

• A. Conduction and Radiation
• B. Condensation and Deposition
• C. Evaporation and Sublimation
• D. Evaporation and Condensation

Answer: (D)

Energy exchange during a phase change happens through latent heat—the energy gained or released as a substance changes its phase without changing temperature. The two processes that directly couple the liquid and its vapor (and thus exchange energy in both directions) are evaporation (liquid to gas, absorbing energy) and condensation (gas to liquid, releasing energy). These are the pair that describes energy transfer through a phase boundary between liquid and vapor.

Other options involve either energy transfer by non-phase-change means (conduction or radiation) or involve different phase boundaries (solid–liquid in melting/freezing, or solid–gas in sublimation/deposition), which is why evaporation and condensation best fit the idea of energy exchange via phase changes alone.