Electronic Devices - Communications - Discussion

In order for a light ray to propagate along a fiber-optic cable, Total internal reflection (TIR) is the phenomenon that must involve i.e., the reflection of all the incident light off the boundary. TIR only takes place when both of the following two conditions are met:

1. The light is in the more dense medium and approaching the less dense medium.

2. The angle of incidence, θi is greater than the so-called critical angle, θc.

A is the answer because the angle of incidence should be more than the critical angle because the critical angle is that angle when a wave passes through an interface.

For total internal reflection, incidence angle must greater then critical angle.

Light propagation in optical fibre uses total internal reflection.

Angle of incidence must be greater than the critical angle.