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The number of photoelectrons emitted for light of a frequency u (higher than the threshold frequency u₀) is proportional to:

Asked in AIPMT 2009 · Conceptual points of the photoelectric effect

Answer: (2) intensity of light

Step-by-step solution

The photocurrent counts electrons freed per second, and each electron is freed by absorbing one photon.

So the number of photoelectrons follows the number of photons arriving per second.

That arrival rate is exactly what intensity measures.

Frequency, threshold frequency and u- u₀ all describe energy per photon, not how many photons arrive.

So the number of photoelectrons is proportional to the intensity of the light.

Why the other options are wrong

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