Radiation obeys certain laws of physics.
Figure 1 - Electromagnetic Spectrum Definition Electromagnetic radiation, or simply radiation, is an advancing disturbance in electric and magnetic field existing in space or in the media. Electromagnetic waves travel at the speed of light and are described by their wavelength and frequency. The speed of light is 300 million meters per second. The wavelength of an electromagnetic wave is measured as the distance from one crest of the wave to the next. The frequency is defined as the rate at which wave crests pass a fixed point.