But heat is EM energy, so some of it is.
Absolutely not. Heat is NOT EM energy.. Doesn't walk like it. Doesn't quack like it either.. EM energy propagates by it's own rules. Has characteristic wavelengths and can fly thru the voids of space with no matter to cling to.. Ahhhh. The beauty of physics is so calming after a session on USMB..
Electromagnetic radiation - Wikipedia the free encyclopedia
Thermal radiation and electromagnetic radiation as a form of heat[edit]
Main articles:
Thermal radiation and
Planck's law
The basic structure of
matter involves charged particles bound together in many different ways. When electromagnetic radiation is incident on matter, it causes the charged particles to oscillate and gain energy. The ultimate fate of this energy depends on the situation. It could be immediately re-radiated and appear as scattered, reflected, or transmitted radiation. It may also get dissipated into other microscopic motions within the matter, coming to
thermal equilibrium and manifesting itself as
thermal energy in the material. With a few exceptions related to high-energy photons (such as
fluorescence,
harmonic generation,
photochemical reactions, the
photovoltaic effect for ionizing radiations at far ultraviolet, X-ray, and gamma radiation), absorbed electromagnetic radiation simply deposits its energy by
heating the material. This happens both for infrared, microwave, and radio wave radiation. Intense radio waves can thermally burn living tissue and can cook food. In addition to infrared
lasers, sufficiently intense visible and ultraviolet lasers can also easily set paper afire.[
citation needed]
Ionizing electromagnetic radiation creates high-speed electrons in a material and breaks chemical bonds, but after these electrons collide many times with other atoms in the material eventually most of the energy is downgraded to thermal energy; this whole process happens in a tiny fraction of a second. This process makes ionizing radiation far more dangerous per unit of energy than non-ionizing radiation. This caveat also applies to the ultraviolet (UV) spectrum, even though almost all of it is not ionizing, because UV can damage molecules due to electronic excitation which is far greater per unit energy than heating effects produce.[
citation needed]
Infrared radiation in the spectral distribution of a
black body is usually considered a form of heat, since it has an equivalent temperature, and is associated with an entropy change per unit of thermal energy. However, the word "heat" is a highly technical term in physics and thermodynamics, and is often confused with thermal energy. Any type of electromagnetic energy can be transformed into thermal energy in interaction with matter. Thus,
any electromagnetic radiation can "heat" (in the sense of increase the
thermal energy termperature of) a material, when it is absorbed.[
citation needed]
The inverse or time-reversed process of absorption is responsible for thermal radiation. Much of the thermal energy in matter consists of random motion of charged particles, and this energy can be radiated away from the matter. The resulting radiation may subsequently be absorbed by another piece of matter, with the deposited energy heating the material.
Thermal radiation is an important mechanism of
heat transfer.[
citation needed]
The electromagnetic radiation in an opaque cavity at thermal equilibrium is effectively a form of thermal energy, having maximum
radiation entropy.[
citation needed]
