Waves

The Total Internal Reflection of Light in Optical Fibres.

What is an Optical Fibre?

An optical fibre is a long thin strand of glass
that has an outer plastic coating. See the picture below.

Optical Fibre

How does an Optical Fibre Work?

Light from a laser enters at one end of the fibre, striking the
surface of the glass at an angle greater than the critical angle.
Total internal reflection occurs at the glass surface and
the light cannot escape until it reaches the other end of the fibre.
The plastic coating prevents the glass surface from getting scratched
which might allow the light to escape through the side of the fibre.


What are the Uses of Optical Fibres?

Optical fibres are used
for telecommunications and to make endoscopes.

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