Einsteins quantum hypothesis for the photoelectric effect

The Einstein photons are light particles—they are localized concentrations of mass, momentum, and energy, and they are propagated like particles. There are usually a very large number of them in a light beam, the energy in any one photon being very small.  

Applying the conservation of energy argument, Einstein showed that the kinetic energy of the ejected electrons where m is mass and u is 

Further work on the photoelectric effect was done in 1916 by the American physicist Robert MuUiken, who succeeded in verifying Einstein s theory in detail. Specifically, he determined the value for Planck s constant h that was in agreement with the value obtained from blackbody radiation. Resist imaging in EUV lithography is based on this photoelectric effect. 

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