What happens to a body's energy when heat is applied to it?

When heat is applied to a body, it increases the energy of that body. In thermodynamics, when heat energy is added to a system, it typically results in an increase in the internal energy of that system. This added energy can manifest as an increase in temperature, increased molecular motion, or even a change in phase, depending on the amount of heat added and the state of the material.

The principle governing this process is based on the first law of thermodynamics, which states that energy cannot be created or destroyed; it can only change forms. When heat is added to a body, its energy increases, allowing for various processes to occur, such as heating up (increasing temperature) or, if the heat continues to be applied and it reaches the necessary threshold, phase changes like melting or vaporization.

Understanding this concept is crucial in power engineering, as managing heat input directly affects the performance and efficiency of systems such as boilers and engines.