Photon

The photon is a particle with no mass (m) and no charge (Q), which travels at the speed of light c in vacuum. The name is derived from the Greek word phos (φῶς), meaning "light".

History

The nature of light has long been disputed. According to the Dutch scholar Christiaan Huygens (1629 – 1695), among others, it was a wave phenomenon, but according to the English scientist Isaac Newton (1643 – 1727) - and many before and after him - it was a stream of particles. It was ultimately the scattering experiments of the American physicist Arthur Holly Compton (1892 – 1962) that provided convincing proof of the particle nature of light.

Quantum mechanics managed to reconcile the wave description and the particle nature of light.

Related concepts

• bremsstrahlung
• characteristic radiation
• compton effect
• electromagnetic radiation
• energy (photon)
• frequency
• pair production
• photoelectric effect
• scattering
• speed of light
• wavelength
• X-radiation