試題詳解

45.An optical fiber has a refractive index of n = 2.0, while the surrounding air has a refractive index of 1.00. If light propagates inside the fiber and is incident on the interface between the fiber and air, at what minimum angle (the critical angle) will total internal reflection occur?
(A) 15°
(B) 30°
(C) 45°
(D) 60°
(E) 89°