The wavelength of light, while it is passing through water is 540 nm . The refractive index of water is 4/3 . The wavelength of the same light when it is passing through a transparent medium having refractive index of 3/2 is \ \ \ \ nm.

Physics · Geometrical Optics

JEE Main 2026 — 22 January, Evening Shift — Question 36

The wavelength of light, while it is passing through water is 540 nm . The refractive index of water is $\frac{4}{3}$ . The wavelength of the same light when it is passing through a transparent medium having refractive index of $\frac{3}{2}$ is $\_\_\_\_$ nm.

Option A:
380
Option B:
840
Option C:
480
Correct
Option D:
540

Answer: C

Step-by-step solution

$\left.\frac{\mu_{1}}{\mu_{2}}=\frac{\mathrm{v}_{2}}{\mathrm{v}_{1}}=\frac{\lambda_{2}}{\lambda_{1}} \right\rvert\, \mathrm{v}=\mathrm{f} \lambda$ $\frac{\mu_{1}}{\mu_{2}}=\frac{\lambda_{2}}{\lambda_{1}}$ $\frac{\mu_{\mathrm{B}}}{3 / 2}=\frac{\lambda}{540}$ $\lambda=\left(\frac{4 \times 2}{3 \times 3} \times 540\right)$ $\lambda=480 \mathrm{~nm}$

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Exam: JEE Main 2026
Paper: 22 January, Evening Shift
Subject: Physics
Chapter: Geometrical Optics
Topic: Introduction to Refraction of Light (Snell's Law)

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Answer: C

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