What is the photoelectric effect?

The photoelectric effect is the ejection of electrons from a metal surface when light of sufficient frequency strikes it. Explained by Einstein using photons.

• Depends on frequency, not intensity higher frequency = more energetic photons = faster electrons.
• Increasing intensity only increases the number of ejected electrons, not their speed.
• Proved that light has particle nature, supporting quantum theory.

Common mistake: Brighter light does not eject faster electrons frequency determines speed; intensity determines count.

The photoelectric effect proves light has particle nature, ejecting electrons from metals when photon energy exceeds the work function.