fotoelektriset

The term "fotoelektriset" refers to the photoelectric effect. This phenomenon occurs when light, or more generally electromagnetic radiation, strikes a material and causes electrons to be emitted from that material. The emitted electrons are called photoelectrons.

The photoelectric effect is a fundamental process in physics and plays a crucial role in many technologies. It was first observed by Heinrich Hertz in 1887 and later explained by Albert Einstein in 1905. Einstein's explanation, which earned him the Nobel Prize in Physics, was based on the idea that light consists of discrete packets of energy called photons. The energy of a photon is directly proportional to the frequency of the light.

When a photon with sufficient energy interacts with an electron in the material, it can transfer its energy to the electron. If this energy is greater than the work function of the material (the minimum energy required to remove an electron from the surface), the electron will be ejected. The excess energy of the photon, beyond the work function, is converted into the kinetic energy of the emitted photoelectron.

The intensity of the light, which relates to the number of photons, affects the number of photoelectrons emitted but not their individual kinetic energy. The frequency of the light, however, is critical. Below a certain threshold frequency, no electrons will be emitted, regardless of the light's intensity. Above this threshold, increasing the frequency increases the maximum kinetic energy of the emitted electrons.

The photoelectric effect is utilized in devices such as photomultipliers, solar cells, and image sensors in digital cameras.