Lights and lasers

A mind map on light and lasers (consists of morse code, endoscopy, laser lighter, sending signals and critical angles)

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  • Created by: zoolouise
  • Created on: 05-05-14 15:01
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  • Lights and lasers
    • Morse Code
      • Morse code uses a series of dots and dashes to represent letters of the alphabet
      • It's used by signalling lamps as a series of short and long flashes of light.
      • Example of a digital signal
    • Sending Signals
      • A signal is sent by light, electricity, microwaves or radio. It's almost instantaneous.
      • It has advantages and disadvantages
        • Can the signal by seen by others? Can wires be cut? How far does the signal have to travel?
    • Laser light
      • White light is made up of different colours of different frequencies out of phase.
      • Laser light has only a single frequency, its in phase and shows love divergence.
      • Laser light's used to read from the surface of a CD.
        • The surface of a CD is pitted, the pits represent the digital signal, laser light's shone onto the CD surface and the difference in the reflection provides the info for the digital signal.
    • Endoscopy
      • Allows doctors to see inside a body without the need for surgery
      • Light passes along 1 set of optical fibres to illuminate the inside of the body, light's reflected and passes up another set of fibres to an eyepiece of camera.
    • Critical angle
      • When light travels from 1 material to another, it's normally refracted
      • If it's passing through a more dense material into a less dense, the angle of refraction is larger than the angle of incidence.
      • Angle of refraction = 90°, the angle of incidence = critical angle.
      • If angle of incidence is bigger than critical angle, light's reflected - total internal reflection.
      • Telephone convos and computer data are transmitted long distances along optical fibres at the speed of light (2000000 km/s in glass)
      • Some fibres are coated to improve reflection.

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