Define "latent heat" in the context of phase changes.

Latent heat refers to the amount of heat absorbed or released by a substance during a phase change without resulting in a temperature change. This phenomenon occurs during transitions such as melting (solid to liquid) and boiling (liquid to gas). During these transitions, energy is used to break or form the intermolecular bonds rather than to increase the temperature of the substance.

For instance, when ice melts, the heat energy added to the ice is used to overcome the attractive forces between the molecules, transitioning it to water without increasing the temperature until all the ice has melted. Similarly, when water boils, the added energy allows the molecules to enter the gaseous phase, again without a change in temperature until the entire liquid has converted to vapor.

Consequently, option B correctly encapsulates the essence of latent heat, highlighting its significance in phase changes. Other choices do not accurately represent latent heat; raising the temperature involves sensible heat (the heat that does change a substance's temperature), and mechanical work or evaporation does not capture the broader definition of latent heat during phase changes.