Radio

Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of light.
Radio waves.Radio waves are a form of electromagnetic radiation, formed whenever a charged object accelerates by a frequency that lies in the radio frequency (RF) portion of the electromagnetic spectrum. This is the variety from a few tens of hertz to a few hundred gigahertz.Electromagnetic radio spectrum
Other types of electromagnetic radiation, with frequencies above the RF range are infrared, visible light, ultraviolet, X-rays and gamma rays. Since the energy of an individual photon of radio frequency is too low to remove an electron from an atom, radio waves are classified as non-ionizing radiation.Radio transmission diagram and electromagnetic waves.Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space equally well, and does not need a medium of transport induces an alternating current and voltage in the conductor. This can be transformed into audio or other signals that carry information. Although the word 'radio' is used to explain this phenomenon, the transmissions which we know as television, radio, radar, and cell phone are all classed as radio frequency emissions.