More generally, electromagnetic waves (of which visible light is one example) are transmitted as a signal that our radios pick up so we can listen to music. Pulses of infrared light are transmitted as signals so we can communicate with our TVs. This section is about the range of all wavelengths or frequencies (including the visible light) over which electromangeitc radiation extends.

White light is actually made up of a rainbow of different colors: violet, indigo, blue, green, yellow, orange and red. There are many other “colors” of light that we cannot see. These include ultraviolet (UV) and infrared (IR) light that is just beyond the range of human vision. They also include more exotic forms of radiation such as X-rays, gamma rays, and radio waves. Together, all of these different “colors” of light are called the electromagnetic spectrum. Thus, the electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation including Visible light, together with these invisible types of lights.

Key terms

• The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.
• The seven members of electromagnetic family are: radio waves, microwaves, infrared light, visible light, ultraviolet light, X-rays and gamma-rays.