Radio

by Vinutha 2010-02-11 14:48:10

Radio

Guglielmo Marconi (1874-1937) of Bologna, Italy, is credited with inventing radio. On December 11, 1901, Marconi surprised the world by transmitting a radio signal in Morse code over a distance of 2,137 miles (3,440 kilometers) from England to Newfoundland, Canada.

Radio is the radiation and detection of signals sent through space as radio waves. Radio waves are a form of electromagnetic radiation having a much longer wavelength (the distance between the crest of one light wave and the crest of the next) than visible light. Radio was initially called "wireless telegraphy" because it performed the same function as a telegraph without using wires. The earliest users of radio were ships, which found it useful to communicate over vast stretches of ocean.

In 1906, American inventor Lee DeForest (1873-1961) built a radio receiver which he called "the Audion."

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