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Physics · 2026 · 1 mark
Dual Nature of Radiation and MatterPhotoelectric Effect and Wave Theory of Light1 markAnalyseassertion reason
CBSE 2026 · Region 5 · Set 1 · Q16
Assertion (A): Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take…
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
(B)
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
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CBSE Class 12 Physics past-paper question from the 2026 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.