(1) Infra-red rays Explanation: The electromagnetic spectrum is the name we use when we talk about different types of radiation as a group. The parts of the electromagnetic spectmm, arranged from highest energy to lowest, are gamma rays, Xrays, ultraviolet light, visible light, infrared light, microwaves, and radio waves. All the parts of the electromagnetic spectrum are the same thing — radiation. Radiation is made up of a stream of photons — particles without mass that move in a wave pattern, all at the same speed — the speed of light.