What is the photoelectric effect? - Leaving Cert Physics - Question i - 2013

The photoelectric effect refers to the phenomenon in which electrons are emitted from the surface of a material when it is exposed to incident light or electromagnetic radiation.

When photons, which are particles of light, strike the surface of a material (typically a metal), they can transfer their energy to the electrons in that material. If the energy of the incoming photons is greater than the work function of the material—this is the minimum energy required to remove an electron from the surface—then electrons will be ejected.

This effect is significant in demonstrating the particle-like behavior of light, supporting the concept of quantized energy levels in the context of quantum mechanics. The importance of the photoelectric effect extends into various applications, including photovoltaic cells and photoelectron spectroscopy.