Physics · Wave Optics

NEET (UG) 2025 — Question 25

An unpolarized light beam travelling in air is incident on a medium of refractive index 1.73 at Brewster's angle. Then -

Option A:
reflected light is completely polarized and the angle of reflection is close to $60^{\circ}$
Correct
Option B:
reflected light is partially polarized and the angle of reflection is close to $30^{\circ}$
Option C:
both reflected and transmitted light are perfectly polarized with angles of reflection and refraction close to $60^{\circ}$ and $30^{\circ}$ , respectively
Option D:
transmitted light is completely polarized with angle of refraction close to $30^{\circ}$

Answer: A

When unpolarised light is incident on a medium of refractive index 1.73 at Brewster's angle then reflected light is

completely polarised.

Using Brewster's Law

$\mu=\tan \left(\mathrm{i}_{\mathrm{p}}\right)$

$1.73=\tan \left(\mathrm{i}_{\mathrm{p}}\right)$

$\mathrm{i}_{\mathrm{p}}=60^{\circ}$

By Law of reflection,

$\mathrm{i}_{\mathrm{p}}=\mathrm{r}=60^{\circ}$

Answer key and solution verified before publishing.

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.