critical angle and optical fibres

critical angle and optical fibres

1. plane mirror

   • light waves reflect from surfaces
   • image in a plane mirror is...
     • virtual
       • cannot be touched/ 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

2. critical angle

   • waves going from a dense medium to a less dense medium speed up at the boundary between them
   • critical angle = 1 / refractive index
     • sin c = 1 / n

3. optical fibres

   • thin rod of high-quality glass
     • very little light is absorbed by the glass
     • light getting in at one end undergoes repeated total internal reflection
   • uses
     • used in endoscopes that allow surgeons to see inside their patients
     • carry enormous amounts of information as pulses of light