Many students have incorrect ideas about a change in light intensity in the photoelectric effect

Quantum and Nuclear


Students may think that a change in the intensity of light affects: the energy of a photon, the stopping voltage, the release of a photoelectron or the energy of a photoelectron. In particular, they might think that an increase in intensity would provide the photon with enough energy to release electrons.

  • Some brief points to consider when planning to introduce the idea of photons to students.

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  • A suggestion for linking the energy delivered by photons to frequency based on the ‘orange liquid’ approach to energy stores. Different sized spoons deliver different volumes of the fluid and therefore different amount of energy.

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  • A discussion of how frequency and energy delivered by photons is related. Use this to help explain why low frequency (low energy) photons are unable to cause the photoelectric effect even when light intensity is high.

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  • Steinburg, R., Oberem, G. and McDermott, L., () Development of a computer-based tutorial on the photoelectric effect, American journal of physics, 64 (11),

    DOI: 10.1119/1.18360

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