Start free

Physics · Geometrical Optics

JEE Main 2026 — 2 April, Evening Shift — Question 14

One side of an equilateral prism is painted by a transparent material of refractive index n2n_2. The refractive index of prism is 1.6. The minimum value of n2n_2 required for total internal reflection from painted face is

Question figure
  1. Option A:

    331.6\frac{3\sqrt{3}}{1.6}

  2. Option B:

    3\sqrt{3}

  3. Option C:

    3.23\frac{3.2}{\sqrt{3}}

  4. Option D:

    435\frac{4\sqrt{3}}{5}

    Correct

Answer: D

Step-by-step solution

At the painted face, critical angle condition: 1.6sin⁡60∘=n2sin⁡90∘1.6\sin60^\circ = n_2\sin90^\circ → n2=1.6×32=435n_2 = 1.6\times\frac{\sqrt{3}}{2} = \frac{4\sqrt{3}}{5}

Solution figure

Answer key and solution verified before publishing.

Practise Geometrical Optics

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

Solve a similar one free
Exam
JEE Main 2026
Paper
2 April, Evening Shift
Subject
Physics
Chapter
Geometrical Optics
Topic
Apparent Depth, Glass Slab, Prism and Dispersion

More Geometrical Optics questions from this paper

One side of an equilateral prism is painted by a transparent material… | JEE Main 2026 PYQ with Solution · DhiX AI