Radio waves

Radio waves have the longest wavelengths in the electromagnetic spectrum. These waves can be longer than a football field or as short as a football. Radio waves do more than just bring music to your radio. They also carry signals for your television and cellular phones.The antennae on your television set receive the signal, in the form of electromagnetic waves, that is broadcasted from the television station. It is displayed on your television screen.

Cable companies have antennae or dishes which receive waves broadcasted from your local TV stations. The signal is then sent through a cable to your house.

Radio frequency energy has also been used in medical treatments, generally for minimally invasive surgeries and coagulation, including the treatment of sleep apnea Magnetic resonance imaging uses radio frequency waves to generate images of the human body.

source:http://en.wikipedia.org/wiki/Radio_waves

http://science.hq.nasa.gov/kids/imagers/ems/radio.html