Electromagnetic waves

Electromagnetic waves

1. Properties

   • All possess both a magnetic wave and an electrical wave interlocked and at right angles to each other
   • All can travel through a vacuum
   • All transverse waves
   • In free space travel at approx. 300,000,000 m/s

2. Types

   • Radio waves
     • Wavelength - 10^-1 - 10^4
     • Frequency - 3x10^9 - 3x10^4
     • Made by electrons oscillated by electric fields in aerials
     • Detected by resonance in electric circuits
     • Used for telecommunications
   • Microwaves
     • Wavelength - 10^-4 - 10^-1
     • Frequency - 3x10^12 - 3x10^9
     • Produced by magnetron, klystron oscillators, using electrons to set up oscillations in a cavity
     • Detected by heating effect and electronic circuits
     • Used for mobile phones, radar, microwave ovens
   • Infrared
     • Wavelength - 7.4x10^-7 - 10^-3
     • Frequency - 4x10^14 - 3x10^11
     • Produced by the oscillation of molecules from all objects at any temp above absolute 0
     • Detected by heating of skin, photographic film
     • Used for heaters, night vision equipment, remote controls
   • Visible light
     • Wavelength - 3.7x10^-7 - 7.4x10^-7
     • Frequency - 8x10^14 - 4x10^14
     • Produced from high-temp solids and gases, lasers
     • Detected by photographic film, retina of eye
     • Used for sight, communication
   • Ultraviolet
     • Wavelength - 10^-9 - 3.7x10^-7
       • Frequency - 3x10^17 - 8x10^14
     • Produced by high-temp solids and gases
     • Detected by photographic film, phosphors and sunburn
     • Used for disco lights,
   • X-Rays
     • Wavelength - 10^-12 - 10^-7
     • Frequency - 3x10^20 - 3x10^15
     • Produced by bombarding metals with high energy electrons
     • Detected by photographic film or fluorescence
     • Used for medical analysis
   • Gamma
     • Wavelength - 10^-16 - 10^-9
     • Frequency - 3x10^17 - 3x10^24
     • Produced by nuclear decay or by a nuclear accelerator
     • Detected by a Geiger counter or photographic film
     • Used for radiotherapy - cancer treatment

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