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JEE Main · 2021 · 27 Aug 2021 · Shift 1 · Modern Physics

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In a photoelectric experiment, increasing the intensity of incident light:
  1. (A)increases the number of photons incident and also increases the K.E. of the ejected electrons.
  2. (B)increases the number of photons incident and the K.E. of the ejected electrons remains unchanged.✓ Correct
  3. (C)increases the frequency of photons incident and increases the K.E. of the ejected electrons.
  4. (D)increases the frequency of photons incident and the K.E. of the ejected electrons remains unchanged

Answer: (B)

Solution

Intensity fixes the number of photons arriving per second, not the energy of each photon. The maximum kinetic energy of a photoelectron, , depends only on the frequency and the work function. Raising the intensity therefore increases the number of incident photons, and hence the photocurrent, while the kinetic energy of the ejected electrons is unchanged.

JEE Main · 2021 · 27 Aug 2021 · Shift 1 · Single correct option

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