Q. An optical fiber made of glass with a core of refractive index of 1.55 and include with another glass with a refractive index of 1.51. Launching takes place from air. What is the value of critical angle for core-clad boundary?
A) $65{^\circ}$
B) $72{^\circ}$
C) $77{^\circ}$
D) $82{^\circ}$
Explanation
(c) $\theta_{c} = \sin^{- 1}{\left( \frac{\mu_{2}}{\mu_{1}} \right) = \sin{\left( \frac{1.51}{1.55} \right) = 77{^\circ}}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.