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Difficulty: EasyPhotoelectric Effect and Work Function

Increasing the intensity of incident monochromatic light of a fixed frequency above the threshold frequency increases the maximum kinetic energy of the photoelectrons emitted from a metal surface.

Answer: Answer

Answer

The statement is False. Increasing light intensity at constant frequency increases the number of emitted photoelectrons per second (photoelectric current), but leaves their maximum kinetic energy unchanged.
The statement is false. In quantum physics, increasing the intensity of monochromatic light increases the photon flux, which elevates the rate of photoelectron emission (photoelectric current). However, the maximum kinetic energy of each photoelectron depends solely on the energy of an individual photon (E=hfE = hf) minus the metal's work function (W0W_0), both of which remain unchanged when intensity is increased at fixed frequency.

Step-by-Step Solution

1
Identify the factors determining maximum kinetic energy in the photoelectric effect.
Maximum kinetic energy KmaxK_{\text{max}} is governed by Einstein's photoelectric equation Kmax=hf−W0K_{\text{max}} = hf - W_0.
Energy transfer occurs on a one-photon-to-one-electron basis.
2
Determine the physical quantity affected by changing light intensity.
Intensity dictates the number of photons striking the metal surface per unit time.
Higher intensity means a greater photon flux, which increases the photoelectron emission rate.
3
Evaluate the statement.
The statement falsely attributes an increase in kinetic energy to an increase in intensity.
Since photon frequency ff and work function W0W_0 remain constant, KmaxK_{\text{max}} does not change.

Key Concept

Independence of photoelectron kinetic energy from light intensity
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Topics

Photoelectric Effect and Work Function

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