Total Internal Reflection
- Optical Fibres can carry visible light over long distances. They do this by the light bouncing off a thin inner core of the glass or plastic.
- Total internal reflection can only work when the wave travles THROUGH A DENSE MATERIAL like glass, to a LESS DENSE MATERIAL like air.
- It all depends whether the angle of incidence is bigger than the critical angle.
Linking With the Refractive Index
THE VALUE OF THE CRITICAL ANGLE DEPENDS ON THE REFRACTIVE INDEX
- A dense material with a high refractive index has a low critical angle.
- If a material has a high refractive index it will totally internally reflect more light.
An endoscope is a thin tube containing optical fibres that let surgeons see inside the body. Endoscops carry two bundles of optical fibres, one to light the part of the persons body and another to carry the image back to the surgeon. The advantage of then is that surgeons are able to perform keyhole surgery.