The critical angle and optical fibres
- Created by: emews
- Created on: 05-11-17 14:58
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- The critical angle and optical fibres
- The image in a plane mirror is:
- virtual (it cannot be touched or projected onto a screen)
- upright (if you stand in front of a mirror, you look the right way up)
- laterally inverted (if you stand in front of a mirror, your left side seems to be on the right in the reflection).
- Waves going from a dense medium to a less dense medium speed up at the boundary between them.
- Beyond a certain angle, called the critical angle, all the waves reflect back into the glass.
- All light waves, which hit the surface beyond this critical angle, are effectively trapped. The critical angle for most glass is about 42°.
- sin c = 1/n
- An optical fibre is a thin rod of high-quality glass. Very little light is absorbed by the glass.
- Uses of optical fibres
- Optical fibres are used in endoscopes that allow surgeons to see inside their patients.
- Optical fibres can also carry enormous amounts of information as pulses of light.
- The image in a plane mirror is:
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