What is Latent Heat?

Latent heat refers to the amount of heat energy absorbed or released by a substance during a phase change that occurs at a constant temperature. This concept is crucial in understanding thermal processes because it describes how energy is used to alter the state of a substance (for example, from solid to liquid or liquid to gas) without changing its temperature during the process.

When a substance undergoes a phase change, such as melting or boiling, the energy goes into breaking molecular bonds rather than increasing the temperature. Thus, when a substance changes from solid to liquid or from liquid to gas, the temperature remains constant, but energy is either absorbed or released in the form of latent heat. This characteristic makes latent heat fundamental in various applications, including meteorology, refrigeration, and heating systems, where phase changes are integral to the process.

The incorrect options provided do not accurately capture this concept. For instance, the choices that suggest a change in temperature occurs alongside the change in state do not reflect the true nature of latent heat. Therefore, the choice that specifies heat transfer that does not change temperature but changes state aptly defines latent heat.