A photon is the carrier of the electromagnetic force. It is the fundamental building block of light.

About the properties of photons
  • A photon is a single indivisible bundle (particle or wave) of energy within an electromagnetic field.
  • A photon is an elementary particle and represents a quantum (plural =quanta) of light – the smallest quantity into which light can be divided.
  • Whilst the field of optics often explains light in terms of waves, this description doesn’t always fit the evidence.
  • Light sometimes exhibits wave-like behaviour, at others, it behaves like both waves and particles or just as particles.

Other properties of photons include:

  • They have zero mass and rest energy. They only exist as moving particles.
  • They are elementary particles despite lacking rest mass.
  • They have no electric charge.
  • They are stable.
  • They carry energy and momentum which are dependent on the frequency.
  • They can have interactions with other particles such as electrons.
  • They can be destroyed or created by many natural processes, for instance when radiation is absorbed or emitted.
  • When in empty space, they travel at the speed of light.