Electromagnetic spectrum. Diagram showing the properties of electromagnetic (EM) radiation. The scales indicate atmospheric penetration (top), wavelength, frequency, and temperature. At the longer wavelength end (left) of the EM spectrum are radio waves, microwaves and infra red radiation. At the shorter wavelength end (right) of the spectrum are gamma rays, X-rays and ultraviolet light. Visible light is a mid-frequency range of wavelengths that can be seen by the human eye.