fotóelektrikushatás

The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. This phenomenon is observed when light strikes a metal surface, causing electrons to be ejected. The term "fotóelektrikushatás" is the Hungarian term for photoelectric effect.

The photoelectric effect cannot be explained by classical physics, which predicted that the energy of the emitted electrons should increase with the intensity of the light. However, experiments showed that the kinetic energy of the emitted electrons depends on the frequency of the light, not its intensity. Above a certain threshold frequency, electrons are emitted regardless of the light's intensity. Increasing the intensity of light above this threshold only increases the number of emitted electrons, not their maximum kinetic energy.

Albert Einstein explained the photoelectric effect in 1905 by proposing that light consists of discrete packets of energy called photons. The energy of each photon is proportional to the frequency of the light, given by the equation E = hf, where E is the energy, h is Planck's constant, and f is the frequency. When a photon strikes an electron in the material, it transfers its energy. If this energy is sufficient to overcome the binding energy of the electron to the material (the work function), the electron is emitted. Any excess energy from the photon is converted into the kinetic energy of the emitted electron.

The photoelectric effect is a fundamental phenomenon in quantum mechanics and has important applications in various technologies, including photomultiplier tubes, solar cells, and image sensors. It was one of the key pieces of evidence that supported the quantum theory of light.