In photoelectric effect, electrons are emitted only when light falls upon a metal surface and exceeds at a certain minimum
Correct answer: C. Frequency
- A. Velocity
- B. Intensity
- C. Frequency
- D. Wavelength
Explanation
In the photoelectric effect, electrons are emitted from a metal surface when the frequency of the incident light exceeds a certain threshold. This is because the energy of the photons, which is needed to overcome the work function of the metal, is directly proportional to the frequency. Intensity increases the number of electrons emitted but does not affect the threshold condition. Wavelength is inversely related to frequency, but it is the frequency that is critical for determining the energy of photons. Velocity is a property of the emitted electrons, not a condition for their emission.
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About Photons and the Particle Model of Light
The particle model treats light as photons with energy E equals hf and momentum related to wavelength. Questions involve the photoelectric effect, work function, threshold frequency, stopping potential and photon energy, while distinguishing particle behaviour from the wave description of interference and diffraction.
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