The maximum kinetic energy of photo-electrons in the photoelectric effect experiment,
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → varies linearly with the frequency of incident light.
By Einstein’s photoelectric equation, each photon gives its energy hν to one electron, which uses the work function φ0 to escape; the rest is its maximum kinetic energy.
\( K_{\mathrm{max}} = h\nu - \phi_{0} \)
This is a straight line against ν with slope h: the maximum kinetic energy varies linearly with frequency (it is not proportional to ν, since the line does not pass through the origin).
Why the other options are incorrect
Option (2) varies in a nonlinear manner with frequency of incident light. — Incorrect. The relation is a straight line, not a curve.
Option (3) does not depend on the nature of the emitting metal. — Incorrect. \( K_{\mathrm{max}} \) depends on the metal through its work function φ0.
Option (4) depends on the intensity of the incident radiation. — Incorrect. Intensity changes the number of photoelectrons (the photocurrent), not their maximum kinetic energy.
NCERT (2026-27):
Effect of Frequency of Incident Radiation on Stopping Potential – “… These observations have two implications: (i) The maximum kinetic energy of the photoelectrons varies linearly with the frequency of incident radiation, but is independent of its intensity.”