Electromagnetic waves consist of two transverse waves: one an oscillating electric field, the other a corresponding magnetic field perpendicular to it. Light, infrared, ultraviolet, radio, and X rays are all examples of electromagnetic waves.

All electromagnetic waves travel at the speed of light when they are in a vacuum. Electromagnetic waves are characterized by their frequency or wavelength and amplitude. Electromagnetic waves differ from other waves in that they do not need a medium such as air, water, or steel through which to travel.