Radiopresentation2
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Radiopresentation2

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    Radiopresentation2 Radiopresentation2 Presentation Transcript

    • Radio waves
      • By Elmer George
    • What is a radio wave?
      • Radio waves are part of the electromagnetic spectrum which is a range of all frequencies of electromagnetic radiations.
      • Different frequency bands transmit radio waves differently.
      • They are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum.
      • Radio waves have frequencies from 300 GHz to as low as 3 kHz
      • They vary in wavelength from around a millimetre to 100,00 km
    • How does a radio wave work?
      • Radio waves are planned to reach local, regional, national and sometimes international areas.
      • AM radio waves use low frequency ground waves so that they can follow the curvature of the earth.
      • FM radio waves use direct waves that travel in straight lines, so they use radio transmitters for long distances.
      • Radio transmitters are electronic devices which with the use on antennas produce radio waves.
    • Electromagnetic spectrum.
      • Electromagnetic spectrum is a range of frequencies of electromagnetic radiation, it extends from a low frequency used for radio to gamma radiation.
      • The Electromagnetic spectrum consists of:
      • radio
      • infrared
      • ultraviolet
      • x-ray
      • gamma ray
    • Television
      • Television travels at the same speed of light roughly 300.000 km/s or 186.000 miles per second.
      • Television is a telecommunication medium for transmitting and receiving moving images, that can be black and white or in colour with or without sound.
      • They have been commercially available since the late 1920’s.
      • It has become a necessity in any household as it is a major tool used in advertising, a source of entertainment and news since the 1970’s.
      • DVD’s, Blue ray and video cassettes have made televisions frequently used for watching recorded and broadcast material.
      • Television recently has become available via the internet such as BBC iplayer and youtube.
    • Microwaves
      • Microwaves have a wave length that is short so it can be measured in centimetres.
      • Microwaves can also be used for transmitting information because they can penetrate light rain, haze, snow, clouds and smoke.
      • Microwaves are also used for radars, it was created to determine the range and detect objects by transmitting short bursts of microwaves, then the object is recorded.
    • Wi-Fi
      • Wifi is wireless networking, it gives you the ability to connect to a PC or network using a radio signal, it is perfect for home and office use.
      • Wifi comes in two speeds 802.11b this transfers data and 11 megabits per second and the more recent 801.11g which goes up to 54 megabits per second.
      • Compared to bluetooth wifi is much faster as bluetooth’s speed is 0.57 megabits per second.
      • wifi has a typical range of 500 feet indoors, laptops and even mobile phones come with wifi built in these days because of the growing use of it.
      • Wifi has become so common that it is offered in most public places even fast food restaurants for example mcdonalds.
    • Infrared Waves
      • Infrared waves are in between the visible and microwave part of the electromagnetic spectrum.
      • “ near infrared” light is closer in wave length to visible light, and “far infrared” is closer to the microwave part of the electromagnetic spectrum.
      • “ far infrared” waves produce heat, they are thermal so we feel this type if wave daily. for example sunlight, radiator and a fire.
      • “ near infrared” are shorter and do not produced any heat, they are the waves used by your television remote.
      • human’s produce infrared waves at normal body temperature.
    • Reference
      • http://science.hq.nasa.gov/kids/imagers/ems/radio.html - Radio wave information
      • http://science.hq.nasa.gov/kids/imagers/ems/infrared.html - Infrared information
      • http://www.filesaveas.com/wifi.html information - Wifi information
      • http://en.wikipedia.org/wiki/Television - Television information