If frequency of light is greater than threshold frequency, then in photoelectric effect the number of electrons increases with an increase in _ of light :
Correct answer: C. Intensity
- A. Frequency
- B. Kinetic energy
- C. Intensity
- D. Momentum
Explanation
In the photoelectric effect, when the frequency of light exceeds a certain threshold frequency, photons can eject electrons from a material. The number of electrons emitted is directly related to the intensity of the light. Intensity measures the number of photons hitting the surface per unit area per unit time; thus, a higher intensity means more photons are available to knock electrons loose. Therefore, increasing the intensity results in more electrons being emitted.Option A (Frequency) is incorrect because while frequency determines the energy of the emitted electrons, it does not influence the number of electrons emitted once the threshold is surpassed. Option B (Kinetic energy) is also incorrect as it relates to the energy of the emitted electrons, not their quantity. Option D (Momentum) does not apply in this context, as it does not affect the count of emitted electrons.
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About Dawn of Modern Physics
Classical physics cannot explain blackbody radiation and related observations, leading to Planck’s quantum theory, in which energy is emitted or absorbed in discrete packets. Photons provide the particle model of light, with energy and momentum linked to frequency and wavelength, including the photoelectric effect and its threshold frequency.
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