Light or infra red radiation is shone along a thin glass fibre and as it hits the glass-air boundary at more than the critical angle it reflects along inside the fibre.
Uses of Fibre Optics
1. Illuminating models or road signs using only one bulb
2. Endoscopy - seeing down inside a patient’s body
3. Communications – sending information along a light beam
4. Security fencing – very difficult to bypass
5. Fibre optic lamp
6.Checking for blockages in drains
Advantages of fibre optics over copper wire
1. Cheap – glass is made from silica, the basic constituent of sand
2. Light in weight – and so it is useful in aircraft
3. The light beam can carry a huge amount of information because its frequency is so high