Question

Light travelling from a transparent medium to air undergoes total internal reflection at an angle of incidence of 45°. Then refractive index of the medium may be

• A. 1.5
• B. 1.3
• C. 1.1
• D. \(1/\sqrt{2}\)

Hint:

TIR occurs when angle of incidence \(\ge\) critical angle.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Critical angle C satisfies \(\sin C = 1/\mu\).
Step 2: Detailed Explanation:
\(C = 45^\circ \rightarrow \mu = 1/\sin 45^\circ = \sqrt{2} = 1.414 \approx 1.5\)
Step 3: Final Answer:
Refractive index is about 1.5.