What is electromagnetic spectrum?
Radiation is a type of energy that moves in the form of waves or particles. This energy is emitted by one body, travels through a substance or space, reflected by some bodies, and ultimately is absorbed by a body. There are different kinds of radiation that differ from each other in their wavelengths and energy. As the wavelength of radiation increases the amount of energy it has decreases.
The diagram show the different types of electromagnetic radiation. This list is called the electromagnetic spectrum. In the diagram, the wavelengths are measured in nanometers (nm), which is equal to one billionth of a meter. The only type of radiation that people can see ranges from 400nm to 700nm. This range of radiation is called visible light. Notice that visible light is made up of the colors of the rainbow (violet, indigo, blue, green, yellow, orange, and red). Violet light with the shortest wavelength is the light color with the most energy. Red light with the longest wavelength is the light color with the least amount of energy.