Radio waves are electromagnetic waves, which owe their existence to moving electrons. James clerk Maxwell first announces the existence of radio waves in 1860, but it was not until 1887 that Heinrich Hertz succeeded in generating them. Sir Oliver lodge first demonstrated wireless telegraphy in 1894, and it was Guglielmo Marconi, the Italian scientist, who could first successfully transmitted a long distance signal in 1900 with the help of radio waves.
Electromagnetic Spectrum and Diagram of Radio Transmission of an Audio Signal.
Radio waves work as the carriers for sound communication signals. The sound signal is modulated with radio waves and transmitted with the help of a transmitter. The modulated signal is received by a radio receiver and then decoded. Radio waves transmit the signals from the broadcasting station to reach our radios. They are used to transmit a variety of programmes. Radio waves were also used to keep in contact with the flying planes and ships in high seas during World War II. With the help of these waves, they are properly guided and controlled during flights thus avoiding accidents and help in reaching their destination safely. All aircrafts and ships are equipped with radio transmitter and receivers.
Radio waves are, in fact, invisible electromagnetic waves, which travel at the speed of light, i.e. at 300,000 kilometers per second. Satellites and spacecrafts keep in contact with earth stations with the help of these waves. Live communication with satellites and astronauts has become possible only due to radio waves. These waves can travel both through the air and vacuum. They can travel in water and underground, but the distance is restricted to a few meters. To study the radio waves originating from the different heavenly bodies, scientists make use of radio telescopes. With the help of these telescopes, it has now possible to identify planets and stars which generate radio waves.
Police also use equipments by which they can send and receive messages while on the move. Fire brigades use radio waves while providing help in accidents. Equipments using these radio waves are used to control traffic and measure the speed of a moving vehicle from a control room.
In a nutshell, we can say that the radio waves have shrunk the world.