Final answer:
Einstein's photoelectric equation, E = hf, explains the quantized nature of EM radiation with photons. It elucidates the photoelectric effect's key features: threshold frequency, kinetic energy of ejected electrons, and the instant ejection of electrons.
Step-by-step explanation:
Albert Einstein's photoelectric equation is E = hf, where E is the energy of a photon, h is Planck's constant, and f is the frequency of the electromagnetic radiation.
This equation is obtained from the photon picture of electromagnetic radiation, which suggests that EM radiation is composed of particles called photons, each with a quantized energy proportional to its frequency.
The photoelectric effect can only be explained using this quantum concept, where photons strike a metal surface and eject electrons.
The three salient features of the photoelectric effect which can be explained by this equation are:
The photoelectric effect occurs only when the photon energy is above a certain threshold, related to the work function of the metal.
The kinetic energy of the ejected electrons is proportional to the frequency of the incident photons minus the work function of the metal.
No delay is observed in the ejection of electrons, regardless of the intensity of the incident light, implying a one-to-one interaction between photons and electrons.