Albert Einstein's 1921 Nobel Prize in Physics was awarded not for relativity but for his explanation of the photoelectric effect — why shining light on a metal knocks electrons loose.
Einstein proposed that light itself comes in discrete packets of energy, later called photons. Only light above a certain frequency frees electrons, no matter how bright — exactly what his quantum picture predicted and classical wave theory could not.
The idea that light is both wave and particle became a cornerstone of quantum mechanics, the theory underpinning modern electronics, from solar cells to the sensors in a phone camera.
Why it matters: Einstein's quanta helped launch quantum physics — the science behind much of the technology we now take for granted.
Written by AI from the linked reports below — original text, not copied from any source. Informational only, not investment advice; verify against the originals.