Question

If a ray of light is incident at a glass surface at the Brewster’s angle of \(60^\circ\), then the angle of refraction inside glass is

• A. \(90^\circ\)
• B. \(60^\circ\)
• C. \(45^\circ\)
• D. \(30^\circ\)
• E. \(15^\circ\)

Hint:

At Brewster angle, reflected and refracted rays are perpendicular.

Answer 1

The Correct Option is D

Concept: At Brewster’s angle: \[ i_p + r = 90^\circ \]

Step 1: Write given data. \[ i_p = 60^\circ \]

Step 2: Apply Brewster condition. \[ i_p + r = 90^\circ \]

Step 3: Substitute value. \[ 60^\circ + r = 90^\circ \]

Step 4: Solve for \(r\). \[ r = 30^\circ \]

Step 5: Conclusion. \[ \boxed{30^\circ} \]