Heat: The form of energy that can be transferred from one system to another as a result of temperature difference.
Thermodynamics is concerned with the amount of heat transfer as a system undergoes a process from one equilibrium state to another.
Heat Transfer deals with the determination of the rates of such energy transfers as well as variation of temperature.
The transfer of energy as heat is always from the higher-temperature medium to the lower-temperature one.
Heat transfer stops when the two mediums reach the same temperature.
Heat can be transferred in three different modes: