Physics Dawn of Modern Physics SZABMU 2024
PMDC Verified Question 3 of 52
The kinetic energy of emitted electrons in photoelectric effect can be increased by increasing ____
A
Frequency of electromagnetic wave
B
Applied potential of electrodes
C
Intensity of incident light
D
Momentum of incident photon
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Frequency of electromagnetic wave
Concept:

Einstein's photoelectric equation maps out exactly what governs the speed (kinetic energy) of electrons ejected from a metal plate.

Formula:

$$ K.E_{max} = hf - \Phi $$

Solution:

  • The work function \( \Phi \) is a constant material property.


  • Therefore, the only variable that directly increases the maximum kinetic energy (\( K.E_{max} \)) of the freed electron is an increase in the incident light's frequency \( f \).


Why other options are incorrect:

Increasing light intensity only increases the number of electrons emitted per second, not their individual speeds. Applied potential helps collect electrons but does not alter their initial ejection kinetic energy.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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