Correct Answer: Total internal reflection

Solution : The correct answer is Total internal reflection .

The fundamental mechanism that allows light to pass through an optical fibre is total internal reflection (TIR) . Optical fibre uses this reflection to "trap" fibre in the fibre's core by choosing core and cladding materials with the appropriate index of refraction. All light will be reflected if the angle is less than a certain degree. We call that "total internal reflection."