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