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Electromagnetic communication. 21 Mar 2012. Learning Objectives. Be able to describe: how radio waves , microwaves and infra-red radiations can be used for communication. Level 5-7 Be able to describe why different radiation is used for different communication . Level 3-5. Light tech.
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Electromagnetic communication 21 Mar 2012
Learning Objectives • Be able to describe: how radio waves , microwaves and infra-red radiations can be used for communication. • Level 5-7 • Be able to describe why different radiation is used for different communication. • Level 3-5
Light tech • Compile a list of different gadgets and gizmo’s that use the following Electromagnetic radiation. (try to link the radiation to the gizmo if you can) • Visible light Infra red Microwave • Radio Ultraviolet
When an electromagnetic wave passes over a conductor something happens
Radio • Our first means of wireless communication, invented by a local. Marconi. • Very long wavelength (km) • Very low frequency (kHz) • Can pass through a lot of materials (people, walls etc.) • Can bounce off the atmosphere • Can be good • Can be bad
Microwaves • Used in Satellites – they pass through the atmosphere more easily. • Much smaller wavelength (cm) • Much higher frequency (MHz – GHz) • Microwaves are absorbed by metals much like radio waves.
Infra-red and visible • Used in Fibre optics: • Law of refraction – Total internal reflection
6 mark question • Explain using what you know about Electromagnetic radiation, which type of radiation is used for TV, Satellite and Endoscopes and why. For full marks you need to explore the relationship between wavelength of EM radiation and transparency of media.