CBSE 2026 · Region 5 · Set 1 · Q16 · 1 mark
Assertion $\displaystyle (A)$ : Photoelectric effect is a spontaneous phenomenon.
Reason (R) : According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.
Official answer
From CBSE’s own marking scheme for this paper.
(B)
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
Dual Nature of Radiation and MatterPhotoelectric Effect and Wave Theory of LightAnalyseassertion_reasonmedium
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CBSE Class 12 Physics past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.