Radiopresentation2

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Radiopresentation2

  1. 1. Radio waves <ul><li>By Elmer George </li></ul>
  2. 2. What is a radio wave? <ul><li>Radio waves are part of the electromagnetic spectrum which is a range of all frequencies of electromagnetic radiations. </li></ul><ul><li>Different frequency bands transmit radio waves differently. </li></ul><ul><li>They are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum. </li></ul><ul><li>Radio waves have frequencies from 300 GHz to as low as 3 kHz </li></ul><ul><li>They vary in wavelength from around a millimetre to 100,00 km </li></ul>
  3. 3. How does a radio wave work? <ul><li>Radio waves are planned to reach local, regional, national and sometimes international areas. </li></ul><ul><li>AM radio waves use low frequency ground waves so that they can follow the curvature of the earth. </li></ul><ul><li>FM radio waves use direct waves that travel in straight lines, so they use radio transmitters for long distances. </li></ul><ul><li>Radio transmitters are electronic devices which with the use on antennas produce radio waves. </li></ul>
  4. 4. Electromagnetic spectrum. <ul><li>Electromagnetic spectrum is a range of frequencies of electromagnetic radiation, it extends from a low frequency used for radio to gamma radiation. </li></ul>
  5. 5. <ul><li>The Electromagnetic spectrum consists of: </li></ul><ul><li>radio </li></ul><ul><li>infrared </li></ul><ul><li>ultraviolet </li></ul><ul><li>x-ray </li></ul><ul><li>gamma ray </li></ul>
  6. 6. Television <ul><li>Television travels at the same speed of light roughly 300.000 km/s or 186.000 miles per second. </li></ul><ul><li>Television is a telecommunication medium for transmitting and receiving moving images, that can be black and white or in colour with or without sound. </li></ul><ul><li>They have been commercially available since the late 1920’s. </li></ul><ul><li>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. </li></ul><ul><li>DVD’s, Blue ray and video cassettes have made televisions frequently used for watching recorded and broadcast material. </li></ul><ul><li>Television recently has become available via the internet such as BBC iplayer and youtube. </li></ul>
  7. 7. Microwaves <ul><li>Microwaves have a wave length that is short so it can be measured in centimetres. </li></ul><ul><li>Microwaves can also be used for transmitting information because they can penetrate light rain, haze, snow, clouds and smoke. </li></ul><ul><li>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. </li></ul>
  8. 8. Wi-Fi <ul><li>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. </li></ul><ul><li>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. </li></ul><ul><li>Compared to bluetooth wifi is much faster as bluetooth’s speed is 0.57 megabits per second. </li></ul><ul><li>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. </li></ul><ul><li>Wifi has become so common that it is offered in most public places even fast food restaurants for example mcdonalds. </li></ul>
  9. 9. Infrared Waves <ul><li>Infrared waves are in between the visible and microwave part of the electromagnetic spectrum. </li></ul><ul><li>“ near infrared” light is closer in wave length to visible light, and “far infrared” is closer to the microwave part of the electromagnetic spectrum. </li></ul><ul><li>“ far infrared” waves produce heat, they are thermal so we feel this type if wave daily. for example sunlight, radiator and a fire. </li></ul><ul><li>“ near infrared” are shorter and do not produced any heat, they are the waves used by your television remote. </li></ul><ul><li>human’s produce infrared waves at normal body temperature. </li></ul>
  10. 10. Reference <ul><li>http://science.hq.nasa.gov/kids/imagers/ems/radio.html - Radio wave information </li></ul><ul><li>http://science.hq.nasa.gov/kids/imagers/ems/infrared.html - Infrared information </li></ul><ul><li>http://www.filesaveas.com/wifi.html information - Wifi information </li></ul><ul><li>http://en.wikipedia.org/wiki/Television - Television information </li></ul>

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