Question

A ray of light is incident at \(30^\circ\) from a medium of refractive index 2 into a medium of refractive index 1. Then the angle of refraction is:

• A. \(30^\circ\)
• B. \(60^\circ\)
• C. \(45^\circ\)
• D. \(90^\circ\)

Hint:

When \(\sin r = 1\), the angle of refraction is \(90^\circ\), indicating the refracted ray grazes the interface.

Answer 1

The Correct Option is D

Use Snell’s law: \[ \mu_1 \sin i = \mu_2 \sin r \] Given: - \( \mu_1 = 2 \), \( \mu_2 = 1 \)
- \( i = 30^\circ \)
\[ 2 \sin 30^\circ = 1 \cdot \sin r \Rightarrow 2 \cdot \frac{1}{2} = \sin r \Rightarrow \sin r = 1 \Rightarrow r = 90^\circ \]