JEE Main 2025 — Atomic Physics Question with Solution
JEE Main 2025 (29 Jan Shift 1)
Question
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Emission of electrons in photoelectric effect can be suppressed by applying a sufficiently negative electron potential to the photoemissive substance.
Reason (R) : A negative electric potential, which stops the emission of electrons from the surface of a photoemissive substance, varies linearly with frequency of incident radiation.
In the light of the above statements, choose the most appropriate answer from the options given below :
Choose an option
Show full solutionCorrect option: D
Correct answer
DBoth and are true but is not the correct explanation of
Step-by-step explanation
Assertion (A) is true because a sufficiently negative potential can repel and stop the emitted electrons from leaving the surface.
Reason (R) is also true because the stopping potential varies linearly with the frequency of the incident light .
However, (R) does not directly explain why a negative potential suppresses electron emission; it only shows how much potential is needed for different frequencies.
Therefore, both (A) and (R) are true, but (R) is not the correct explanation of (A).
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This is a previous-year question from JEE Main 2025, covering the Atomic Physics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.