Incandescence

Incandescence is the release of electromagnetic radiation from a hot body due to its high temperature. The release of radiation is usually the infrared (heat) and visible light areas of the spectrum. Incandescence occurs in both light bulbs where the resistance of electron flow excites electrons in the material to jump to a higher orbital and thus subsequently release a photon, and when something is 'on fire' or during an explosive reaction or a combustion reaction.

Also Note

• X-rays can also be produced by incandescence, often most energy is wasted in the form of heat.