Photon (Gr. Phos - Light)

A photon is a particle of electromagnetic radiation, representing one quantum of radiant energy.

Photons are massless elementary particles that move at the speed of light and have a dual wave-corpuscular nature. They are quanta of the electromagnetic field and carry electromagnetic interaction.

The energy of a photon is directly proportional to the frequency of electromagnetic radiation and is described by Planck’s equation E=hν, where E is the photon energy, h is Planck’s constant, ν is the frequency of radiation. It is photons that form electromagnetic radiation in its entire spectrum - from radio waves to gamma radiation.

Photons play a key role in many physical processes and phenomena - the photoelectric effect, the Compton effect, the emission and absorption of light by atoms and molecules. Their study made it possible to formulate modern ideas about electromagnetic radiation and the interaction of light with matter.