An antenna (plural antennae or antennas), or aerial, is an electrical device which converts electric power into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver. In transmission, a radio transmitter supplies an electric current oscillating at radio frequency (i.e. a high frequency alternating current (AC)) to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of an electromagnetic wave in order to produce a tiny voltage at its terminals, that is applied to a receiver to be amplified. COUNT 5
QSN1 What device is able to change electric powerinto radio waves and also do the reverse? ANS1 An antenna QSN2 What device is often used in conjuntion with the antenna? ANS2 radio transmitter or radio receiver QSN3 What process associated with antennas produces a high frequency alternating current? ANS3 transmission QSN4 What else can radio waves be called? ANS4 electromagnetic waves QSN5 When does an antenna catch electromagnetic waves? ANS5 reception