The Significance of Einstein's Photon Theory

[jmorris]

Einstein showed that light consists of photons which are wave packets of electromagnetic radiation, each carrying energy hf, where f is the frequency of the radiation. The photon is the least quantity or ‘quantum’ of electromagnetic radiation and may be considered as a massless particle. It has a dual ‘wave–particle’ nature in that its particle-like nature is observed in the photoelectric effect and its wave-like nature is observed in diffraction and interference experiments such as Young’s double slits experiment.