Gamma rays have the smallest wavelength of all the electromagnetic waves. The wavelength of gamma rays is usually less than 10 -12 meters. Radio waves have that largest wavelength of all the electromagnetic waves. Radio waves have a wavelength between 1 millimeter and 100 kilometers.
Electromagnetic waves are transverse waves that do not require a medium through which to travel. Therefore, electromagnetic waves can travel through a vacuum such as empty space. The wavelength of an electromagnetic waves is the distance between two consecutive crests or two consecutive troughs.
Gamma rays are produced from radioactive atoms. Because of their small wavelengths and high frequencies, gamma rays are able to pass through the tissues of organisms. Therefore, gamma rays are often used in medical procedures used to treat internal organs. For example, gamma rays are used to kill cancer cells.
Radio waves may be created naturally by lightning or astronomical objects. Radio waves can also be created artificially. Radio waves are most often used for communication, broadcasting, radar, navigation systems, etc.