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Physics vocabulary · Quantum and Modern Physics

Photoelectric effect

Meaning in physics, with examples

nounCommon term

In physics, photoelectric effect means: The release of electrons from a metal surface when light of high enough frequency shines on it. It showed that light energy comes in packets called photons.

In Turkish: fotoelektrik olay, fotoelektrik etki

How it is used

Below a threshold frequency no electrons are emitted, however bright the light. Einstein explained it in 1905 with hf = φ + KEmax, where φ is the work function, and his Nobel Prize was awarded mainly for this work. It is used in light detectors such as photomultiplier tubes.

Example sentences

  1. In the photoelectric effect, brighter light releases more electrons, but not faster ones.

  2. Ultraviolet light produces the photoelectric effect in zinc, but red light does not.

Common collocations

  • threshold frequency
  • work function
  • photoelectrons
  • stopping potential
  • photonA single packet, or quantum, of electromagnetic energy. Its energy depends only on the frequency of the radiation: E = hf, where h is Planck's constant.
  • electronA very light particle with a negative charge of about −1.6 × 10⁻¹⁹ C, found around the nucleus of every atom. Moving electrons carry the current in metal wires.
  • quantumThe smallest separate amount of a physical quantity, such as energy, that can be absorbed or emitted. Light energy, for example, comes in quanta called photons.
  • wave-particle dualityThe idea that light and matter can behave both as waves and as particles, depending on the experiment. Electrons, for example, can produce interference patterns.
  • frequencyThe number of complete waves or oscillations that pass a point, or happen, each second. It is measured in hertz (Hz), where 1 Hz means one cycle per second.

More terms: Quantum and Modern Physics

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