The photoelectric effect is the emission of electrons or other free carriers when light shines on a material. It is a key part of the operation of many technologies, including solar cells, photodiodes, and photomultipliers.
The threshold frequency for a given material is the minimum frequency of light that can cause the photoelectric effect to occur. For frequencies below the threshold frequency, no electrons will be emitted, no matter how intense the light is.
For frequencies above the threshold frequency, the number of emitted electrons is proportional to the intensity of the light. This means that brighter light will eject more electrons than dimmer light of the same frequency.
The energy of an individual emitted electron is also proportional to the frequency of the light. This means that higher frequency light will eject electrons with more energy than lower frequency light.
