Phase change from solid to liquid.

• A. Melting
• B. Freezing
• C. Evaporation
• D. Condensation

Answer: (A)

Melting is the transition from a solid to a liquid, happening when the particles gain enough energy to break free from the fixed positions in the solid’s lattice and flow as a liquid. As you heat a solid, its temperature rises until you reach the melting point; at that temperature, added heat goes into overcoming the forces holding the particles together rather than raising the temperature, so the substance can be partly solid and partly liquid during the change. This energy input is the latent heat of fusion. Once all of it has melted, further heating increases the temperature of the liquid. Among the options, melting is the solid-to-liquid change. Freezing is the reverse (liquid to solid), evaporation is liquid to gas, and condensation is gas to liquid.