In 1921, Einstein was awarded the Nobel Prize in Physics for Photoelectric Effect.
Source(s):
Pls refer to my article dated February 8, 2008:
http://great-scientists.suite101.com/article.cfm/albert_einstein_scientist

Permalink | Report

It was the photoelectric effect. "In 1905, Einstein solved this paradox by describing light as composed of discrete quanta, now called photons, rather than continuous waves. Based upon Max Planck's theory of black-body radiation, Einstein theorized that the energy in each quantum of light was equal to the frequency multiplied by a constant, later called Planck's constant. A photon above a threshold frequency has the required energy to eject a single electron, creating the observed effect. This discovery led to the quantum revolution in physics and earned Einstein the Nobel Prize in 1921."
Source(s):
http://en.wikipedia.org/wiki/Photoelectric_effect

Permalink | Report

He did not won the Nobel prize for any particular invention, but for his papers on physics.
Permalink | Report

If you're wondering what the photoelectric effect is, Einstein noticed that if you shine light on a metal, it gives off electrons. By varying the "color" (wavelength) of the light (red, blue, etc but also infrared and ultraviolet, and other parts of the spectrum) and also the brightness, he was able to prove the existence of photons, or that light can be thought of not just as waves, but also as particles.

This was a much bigger deal than it sounds like outside of science. It also led to the invention of many of the electronics in your apartment.
Permalink | Report