An optical fiber is made with core material of index of refraction 1.30. The fiber is clad with a material of index 1.50. What is the critical angle for this fiber?
A) 53.1°
B) 56.4°
C) 60.1°
D) With these indices, there is not critical angle.

Question

Quizplus · Accepted Answer

The critical angle occurs when light travels from a medium with a higher index of refraction to a medium with a lower index. Here, the core has a lower index than the cladding, so total internal reflection cannot occur, and thus there is no critical angle.

An Optical Fiber Is Made with Core Material of Index