Article: Radiation

For other uses, see Radiation (disambiguation).

Radiation in physics is a process of emission of energy in the form of waves or particles. Various types of radiation may be distinguished, depending on the properties of the emitted energy/matter, the type of the emission source, properties and purposes of the emission, etc.

Radiation by type of emission

• Electromagnetic radiation, a stream of photons.
  • Gamma radiation, which is high-energy electromagnetic waves.
• Gravitational radiation, a predicted consequence of general relativity.
• Particle radiation, radiation by means of particles that have a rest mass.
  • Alpha radiation, composed of the nuclei of helium-4 atoms.
  • Beta radiation, consisting of energetic electrons or positrons.
  • Neutron radiation

Radiation by source/cause of emission

• Particle:
  • Delta radiation
  • Epsilon radiation

• E/m:
  • Cherenkov radiation, electromagnetic radiation by a particle moving through an insulating medium faster than the speed of light in that medium.
  • Synchrotron radiation, radiation by a charged particle undergoing acceleration.
  • Solar radiation, radiation emitted by the sun.
  • Thermal radiation, emission of electromagnetic radiation by a hot object
  • Hawking radiation, thermal radiation thought to be emitted by black holes due to quantum effects.

Radiation by properties of emission

• Ionizing radiation, radiation with sufficient energy to cause ionization.
• Non-ionizing radiation, radiation that does not carry enough energy to directly cause ionization.

See also

• Radioactive decay
• Radioactive contamination
• Radiant energy, radiation emitted by a source into the surrounding environment.
• Background radiation
• Radiation poisoning