Waves
- Created by: Ellie
- Created on: 02-06-13 15:54
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- Waves
- The basics
- amplitude
- height of wave
- wavelength
- distance from 1 peak to next
- frequency
- no. of complete waves per second
- period
- time for 1 complete wave
- speed = frequency x wavelength
- transverse
- light & EM waves
- longitudinal
- sound & ultrasound
- compressions
- amplitude
- Electromagnetic spectrum
- Radio
- longest wavelength
- lowest frequency
- communications
- Microwaves
- ovens
- satellite communications
- heat human body tissues
- Infrared radiation
- night vision
- skin burns
- Visible light
- photography
- optical fibres
- Ultraviolet
- fluorescent lamps
- blindness
- X-rays
- see inside things
- Gamma rays
- sterilising
- cancer
- Radio
- Reflection refraction and diffraction
- Diffraction
- gap wider than wavelength
- little diffraction
- gap slightly wider than wavelength
- diffraction at edges
- gap the same as wavelength
- maximum diffraction
- gap wider than wavelength
- Relection
- angle of incidence = angle of reflection
- mirror
- object -> mirror = incident ray
- eye -> mirror = reflected ray
- object in mirror = virtual
- Refraction
- EM waves are slower in denser material
- When light gos into a denser medium it bends towards the normal
- Triangular prisms disperse white light
- ROYGBIV
- Refractive index
- Glass = 1.5
- Water = 1.3
- = sin(i)/sin(r)
- critical angle
- =1/refractive index
- angle of incidence is < critical angle
- most of the light passes out
- angle of incidence is > critical angle
- it reaches total internal reflection
- angle of incidence = critical angle
- the emerging ray comes along the surface
- Diffraction
- Analogue and digital
- analogue
- can take any value
- amplifying amplifies noise
- digital
- can only take 2 values
- multiplexing is when multiple digital signals are sent
- quantisation is the process of rounding values
- analogue
- Sound
- humans hear between 20 and 20000 HZ
- the denser the medium the faster it travels
- Oscilloscopes
- Turns sound waves into electrical signs,s
- The higher the peaks the louder it is
- The more peaks the higher the pitch
- The basics
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