15.5 Photoelectric Effect

Photoelectric Effect

The Photoelectric Effect occurs when electrons are emitted from electromagnetic radiation, usually light, hitting a photoactive material, usually a metal. As discussed previously, if electrons are given enough energy, they will escape the nucleus of the atom they were bound to and be emitted.

The removal of electrons from atoms requires a minimum amount of energy, this is called the work function, which is represented with the variable ${\phi}$. For different materials, the work function will vary. This minimum energy that the photon has to be at to cause the photoelectric effect is also related to the frequency of the light through the equation ${E=hf}$. This minimum frequency required for the light to remove the electron from the atom is called the threshold frequency. If the photons that are hitting the atom are not at the threshold frequency, the photoelectric effect will not occur as the electrons will never leave the atom, but simply go up in energy level.