An optic fiber is made of clear plastic with an index of refraction of 1.50.For what range of angles of incidence θ with the lateral surface of the fiber will light remain inside the plastic "guide" if it is surrounded by air?
A)21.1°

Question

An optic fiber is made of clear plastic with an index of refraction of 1.50.For what range of angles of incidence θ with the lateral surface of the fiber will light remain inside the plastic "guide" if it is surrounded by air?
A)21.1° < θ < 90°
B)23.4° < θ < 90°
C)38.3° < θ < 90°
D)40.3° < θ < 90°
E)41.8° < θ < 90°

Quizplus · Accepted Answer

The critical angle for total internal reflection is calculated using Snell's law. For the plastic-air interface, the critical angle is given by θc = arcsin(1/1.50) ≈ 41.8°. Thus, light will remain inside the fiber for angles greater than 41.8°.

An Optic Fiber Is Made of Clear Plastic with an Index