In the process of energy transfer, what is it called when energy is not usefully transferred as output?

Energy that is not usefully transferred as output is termed "wasted energy." This refers to the energy that is lost in a system and does not contribute to the intended work or function. In various processes, some energy may be released in forms that do not do useful work, such as heat, sound, or light, which dissipate rather than perform a desired task.

For instance, in an electric motor, if not all the electrical energy is converted into mechanical energy, the remaining energy may be lost as heat due to resistance in wires, or as sound produced by the machine's operation. This wasted energy is a significant concept in the study of energy efficiency, as it highlights where improvements can be made to ensure that more of the energy supplied is converted into a useful form. Understanding wasted energy is vital for both academic physics and practical applications in engineering and energy conservation.