What is latent heat?

Latent heat refers to the energy that is absorbed or released during a phase change of a substance, such as when it transitions between solid, liquid, and gas states, without a change in temperature. This concept is crucial in understanding processes like melting, freezing, vaporization, and condensation.

When a substance changes its physical state, like ice melting into water or water boiling into steam, it requires energy input or releases energy, but the temperature remains constant during this change. Thus, the designation "latent" means this energy is hidden in the process of changing states. The energy is not reflected in a temperature change but is essential for overcoming the forces that hold molecules together in a solid or liquid form.

This foundational principle in thermodynamics explains why option B is the correct answer, as it encompasses the broader definition of latent heat encompassing all forms of state changes, rather than focusing solely on one specific phase transition or energy type.