Photon
Astrophysics
A photon is both a wave and a particle. A beam of light is composed of these particles. Even though a photon is a particle, it is still a wave and has a wavelength, period, frequency, and so on, like any other wave (ie. sound, water, slinky.) A photon is usually represented (as in this website) by a squiggle traveling in a certain direction.
- — The Universe Adventure Glossary retrieved 2014-05-20
Energy
Science› Energy› Renewable Energy
Solar Energy
A particle of light that acts as an individual unit of energy.
- — Solar Energy Development PEIS Glossary retrieved 2014-06-15
Nuclear Physics
A quantity of electromagnetic energy. Photons have momentum but no mass or electrical charge.
- — Glossary of Nuclear Science Terms retrieved 2014-05-20
Defense
A unit or "particle" of electromagnetic radiation, carrying a quantum of energy, which is characteristic of the particular radiation.
Telecommunications
A discrete packet, i.e., quantum, of electromagnetic energy. Note: The energy of a photon is h
, where h is Planck's constant and is the frequency of the electromagnetic wave.