CBSE 2025 · Region 5 · Set 3 · Q1 · 1 mark
A beam of light of wavelength $\displaystyle 720$ nm in air enters water (refractive index $\displaystyle =\frac{4}{3}$ ) . Its wavelength in water will be:
Official answer
From CBSE’s own marking scheme for this paper.
(A)
$\displaystyle 540$ nm
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CBSE Class 12 Physics past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.