| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 1,728,805,367 visitors served. |
|
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
photon |
Also found in: Encyclopedia, Wikipedia, Hutchinson | 0.01 sec. |
|
photon /pho·ton/ (fo´ton) a particle (quantum) of radiant energy.
Photon A light particle. Mentioned in: Positron Emission Tomography (PET)
photon [fō′ton] Etymology: Gk, phos, light the smallest quantity of electromagnetic energy. It has no mass and no charge but travels at the speed of light. Photons may occur in the form of x-rays, gamma rays, or quanta of light. The energy (E) of a photon is expressed as the product of its frequency (v) and Planck's constant (h), as in the equation E = hv. X-ray photons occur in frequencies of 1018 to 1021 Hz and energies that range upward from 1 KeV. photon (fō´ton), n a bullet or quantum of electromagnetic radiant energy emitted and propagated from various types of radiation sources. The term should not be used alone but should be qualified by terms that will clarify the type of energy (e.g., light photon, radiographic photon).
photon a particle (quantum) of radiant energy. x-ray photon
a particle of x-ray energy. photon The basic unit of radiant energy defined by the equation E = hν where h is Planck's constant (6.62 ✕ 10−34 joule ✕ second), ν the frequency of the light and E the energy difference carried away by the emission of a single photon of light. The term photon usually refers to visible light whereas the term quantum refers to other electromagnetic radiations. See quantum theory; wave theory; troland.How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
|
| ? Mentioned in | ? References in periodicals archive | |
|---|---|---|
These principles teach us in both conceptual and practical ways, that the energy of light can penetrate physical matter and interact with it in ways that could not take place if it were actually solid and impenetrable. |
| Medical Dictionary |
| Free Tools: |
For surfers:
Free toolbar & extensions |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup | Partner with us |
|---|