A fiber optic cable (n = 1.40)is submerged in water (n = 1.33).What is the critical angle for light to stay inside the cable?

Question

Quizplus · Accepted Answer

The critical angle for total internal reflection can be calculated using the formula sinθc = n2/n1, where n2 is the refractive index of the first medium (water) and n1 is the refractive index of the second medium (fiber optic cable). Plugging in the values given, we get sinθc = 1.33/1.40, which yields θc = sin^-1(1.33/1.40) = 71.8°. Therefore, light entering the fiber optic cable at an angle greater than 71.8° will be reflected back into the cable.

A Fiber Optic Cable (N = 1