In the photoelectric effect, increasing the intensity of the incident light while keeping the frequency fixed increases

  • A. the maximum kinetic energy of the emitted electrons
  • B. the number of electrons emitted per second
  • C. the threshold frequency
  • D. the work function of the metal

Explanation

More intense light means more photons per second, so more electrons are ejected, but each photon still carries the same energy hf and so gives each electron the same maximum kinetic energy. Only raising the frequency raises that energy. The failure of the wave theory to predict this is the strongest evidence for the particle nature of light.

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