Compton (1892-1962) on scattering of X-rays from electrons In
1921, Einstein was awarded the Nobel Prize in Physics for his contribution
to theoretical physics and the photoelectric effect In 1923, Millikan was
awarded the Nobel Prize in physics for his work on the elementary
charge of electricity and on the photoelectric effect We can summarise the photon picture of electromagnetic  radiation
as follows:
(i)
In interaction of radiation with matter, radiation behaves as if it is
made up of particles called photons