Product Code Database
In physics, and in particular as measured by radiometry, radiant energy is the energy of electromagnetic" Radiant energy". Federal standard 1037C and gravitational radiation. As energy, its SI unit is the joule (J). The quantity of radiant energy may be calculated by Integral radiant flux (or radiant flux) with respect to time. The symbol Qe is often used throughout literature to denote radiant energy ("e" for "energetic", to avoid confusion with photometric quantities). In branches of physics other than radiometry, electromagnetic energy is referred to using E or W. The term is used particularly when electromagnetic radiation is emitted by a source into the surrounding environment. This radiation may be visible or invisible to the human eye.George Frederick Barker, Physics: Advanced Course, page 367Hardis, Jonathan E., " Visibility of Radiant Energy". PDF.
The term "radiant energy" also applies to gravitational radiation. For example, the first gravitational waves ever observed were produced by a black hole collision that emitted about 5.3 joules of gravitational-wave energy.
EM radiation can have various frequency. The bands of frequency present in a given EM signal may be sharply defined, as is seen in atomic spectra, or may be broad, as in blackbody radiation. In the particle picture, the energy carried by each photon is proportional to its frequency. In the wave picture, the energy of a monochromatic wave is proportional to its intensity. This implies that if two EM waves have the same intensity, but different frequencies, the one with the higher frequency "contains" fewer photons, since each photon is more energetic.
When EM waves are absorbed by an object, the energy of the waves is converted to heat (or converted to electricity in case of a photoelectric material). This is a very familiar effect, since sunlight warms surfaces that it irradiates. Often this phenomenon is associated particularly with infrared radiation, but any kind of electromagnetic radiation will warm an object that absorbs it. EM waves can also be reflected or scattering, in which case their energy is redirected or redistributed as well.
Various other applications of radiant energy have been devised. Class 250, Radiant Energy , USPTO. March 2006. These include treatment and inspection, separating and sorting, medium of control, and medium of communication. Many of these applications involve a source of radiant energy and a detector that responds to that radiation and provides a signal representing some characteristic of the radiation. Radiant energy detectors produce responses to incident radiant energy either as an increase or decrease in electric potential or electric current flow or some other perceivable change, such as exposure of photographic film.
|
|
