Heat

In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a divergence in temperature. In thermodynamics, the quantity TdS is used as a commissioner measure of heat, which is the absolute temperature of an object multiplied by the differential quantity of a system's entropy measured at the boundary of the object. Heat can flow suddenly from an object with a high heat to an object with a lower temperature. The transfer of heat from an object, to another object with an equal or higher temperature, however, can happen only with the aid of a heat force.

High temperature bodies, which often result in high rates of heat transfer, can be created by chemical reactions (such as burning), nuclear reactions (such as fusion taking place inside the Sun), electromagnetic indulgence (as in electric stoves), or mechanical dissipation (such as friction). Heat can be transferred between objects by an emission, conduction and convection. Temperature is used as a measure of the inside energy or enthalpy, that is the level of elementary motion giving rise to heat transfer. Heat can only be transferred between objects, or areas within an object, with different temperatures (as given by the zeroth law of thermodynamics), and then, in the absence of work, only in the direction of the colder body (as per the second law of thermodynamics). The temperature and phase of a material subject to heat transfer are determined by latent heat and heat capacity. A related term is thermal energy, loosely defined as the energy of a body that increases with its temperature.