radiationphotons

Radiation photons are the quanta of the electromagnetic field that constitute electromagnetic radiation. They are massless gauge bosons with spin 1, two helicity states, and no electric charge. In vacuum they propagate at the speed of light and carry both energy and momentum.

The energy of a photon is proportional to its frequency, E = hν, or inversely proportional to its wavelength, E = hc/λ. Photons can be created in atomic and molecular transitions, thermal emission, and a variety of quantum processes such as synchrotron radiation and bremsstrahlung. They are absorbed or scattered by matter through interactions described by quantum electrodynamics, including the photoelectric effect, Compton scattering, and, at higher energies, pair production.

In quantum electrodynamics, photons are excitations of the quantized electromagnetic field. They can be created and annihilated in interactions with charged particles, so their number is not conserved; however total energy and momentum in a closed system are conserved. Their interactions depend on energy, wavelength, and the properties of the matter they encounter.

Radiation photons cover a broad spectrum from radio waves to gamma rays. They are central to many areas of science and technology, including astronomy, medical imaging and therapy, communications, and safety engineering, where shielding and exposure management are important considerations.