What does the term "latent heat" refer to?

The term "latent heat" specifically refers to the heat that is absorbed or released during a phase transition of a substance, without any change in temperature. This concept is crucial in thermodynamics and phase change processes, such as melting (solid to liquid) or vaporization (liquid to gas).

During these phase changes, energy is utilized to change the internal structure of the substance rather than increasing its temperature. For example, when ice melts to become water at 0°C, the heat added is used to break the bonds holding the water molecules together in the solid state, allowing them to move freely as a liquid while the temperature remains constant. This is why the correct answer focuses on the requirement of heat for changing phases, emphasizing that this process occurs without a temperature change. Understanding this principle is essential for studying various real-world phenomena, such as weather patterns, refrigeration processes, and heating systems.