OPTICAL FIBRES:allow keyhole surgery(surgery without large incisions)
REFRACTION: the speed of light changes with the density of the material it enters!This change in speed may cause a change in direction..this is known as refraction.
LIGHT IS REFLECTED AT THE BOUNDARY BETWEEN THE MATERIAL AND THE AIR..THIS IS KNOWN AS TOTAL INTERNAL REFLECTION.
TOTAL INTERNAL REFLECTION ALLOWS THE LIGHT TO TRAVEL ROUND THE BEND.
when light passes from a more dense material to a less dense material e.g from glass to air the angle of refraction will be greater than the angle of incidence.
if you were to increase the angle of incidence then it is possible for it to reach 90 degees .If this happens it is known…