Which property allows a material to become a liquid when heated?

• A. Fusibility
• B. Malleability
• C. Conductivity
• D. Density

Answer: (A)

Fusibility is the key property that describes a material's ability to become molten or liquid when subjected to heat. When a material has a high fusibility, it means that it can transition from a solid state to a liquid state at relatively low temperatures. This property is essential in processes such as welding, casting, and metalworking, where materials need to be melted for shaping or joining.

In contrast, malleability refers to the ability of a material to deform under compressive stress, typically when hammered or rolled, which does not directly address the material's phase change when heated. Conductivity relates to a material's ability to conduct electricity or heat, which is also not relevant to the transition between solid and liquid. Density, while important for understanding mass per unit volume, does not speak to the phase change of a material under heat. Therefore, fusibility is the correct term that encapsulates the property allowing a material to become a liquid when heated.