Answer to Question #162598 in Optics for Gill Allain

Question

Describe fully

(a) One natural phenomenon due to total internal reflection.

(b) one practical application of it.

Answer 1

(a) One natural phenomenon due to total internal reflection is a mirage. The air above a hot pavement heats up and its refractive index decreases. The light coming from the sky far in front of us moves in a medium of greater refractive index because the air is colder there. So, this light experiences total internal reflection and what we see is not a paddle of water but a reflection of blue sky on the road.

(b) One practical application of it is optical data transmission in cables (optical fiber). Lasers flash according to input digital signals, the light experiences multiple reflections at the surface between the fiber and air and continues its propagation inside the fiber.