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Question: Answered & Verified by Expert
A monochromatic light is incident at a certain angle on an equilateral triangular prism and suffers minimum deviation.

If the refractive index of the material of the prism is $\sqrt{3}$,

then the angle of incidence is :
PhysicsRay OpticsJEE MainJEE Main 2019 (11 Jan Shift 2)
Options:
  • A $90^{\circ}$
  • B $30^{\circ}$
  • C $60^{\circ}$
  • D $45^{\circ}$
Solution:
1104 Upvotes Verified Answer
The correct answer is: $60^{\circ}$
For minimum deviation:

$\mathrm{r}_{1}=\mathrm{r}_{2}=\frac{\mathrm{A}}{2}=30^{\circ}$

by Snell's law $\mu_{1} \sin \mathrm{i}=\mu_{2} \sin \mathrm{r}$

$1 \times \sin i=\sqrt{3} \times \frac{1}{2}=\frac{\sqrt{3}}{2} \Rightarrow i=60$

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