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Physics · Wave Optics

JEE Main 2024 — 31 January, Shift 2 — Question 34

When unpolarized light is incident at an angle of 60∘60^{\circ} on a transparent medium from air.The reflected ray is completely polarized. The angle of refraction in the medium is

  1. Option A:

    30∘30^{\circ}

    Correct
  2. Option B:

    60∘60^{\circ}

  3. Option C:

    90∘90^{\circ}

  4. Option D:

    45∘45^{\circ}

Answer: A

Step-by-step solution

Given: incidence angle i=60∘, reflected ray is completely polarized.\mathrm{Given:\ incidence\ angle}\ i = 60^\circ, \ \mathrm{reflected\ ray\ is\ completely\ polarized.} Condition: i=iB (Brewster′s angle).\mathrm{Condition: }\ i = i_B \ (\mathrm{Brewster's\ angle}). tan⁡iB=μ⇒μ=tan⁡60∘=3.\tan i_B = \mu \quad \Rightarrow \quad \mu = \tan 60^\circ = \sqrt{3}. Using Snell′s law: n1sin⁡i=n2sin⁡r,\mathrm{Using\ Snell's\ law: }\ n_1 \sin i = n_2 \sin r, 1⋅sin⁡60∘=3⋅sin⁡r⇒sin⁡r=sin⁡60∘3.1 \cdot \sin 60^\circ = \sqrt{3} \cdot \sin r \quad \Rightarrow \quad \sin r = \frac{\sin 60^\circ}{\sqrt{3}}. sin⁡r=323=12⇒r=30∘.\sin r = \frac{\tfrac{\sqrt{3}}{2}}{\sqrt{3}} = \tfrac{1}{2} \quad \Rightarrow \quad r = 30^\circ.
Solution figure

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Exam
JEE Main 2024
Paper
31 January, Shift 2
Subject
Physics
Chapter
Wave Optics
Topic
Polarization of Light Waves
When unpolarized light is incident at an angle of 60 ° on a… | JEE Main 2024 PYQ with Solution · DhiX AI