Einstein showed that the photoelectric effect could be understood by:

Treating light as a stream of particles

Treating the photoelectrons as waves

Treating light as an electromagnetic wave

Ignoring the energy of the light

Einstein showed how the photoelectric effect could be understood

by treating light as a stream of particles, with each particle's energy

depending on the color of the light.

Einstein is famous for his work in Relativity. But it was his explanation

of the photoelectric effect ... now a pretty obscure topic ... that won him

his only Nobel Prize.