Photoelectric Effect: The Theory
Einstein’s explanation: Suppose the energy in the light is concentrated in particle-like objects (now we call them photons) whose energy depend on the frequency of the light according to Planck’s equation: E = h?.
Prediction: Maximum energy of electrons liberated = energy of photon - binding energy of electron. Emax = h? - h?0
Experiment: done accurately by Millikan in 1916: