The electromagnetic spectrum is the term used to represent the broad range of frequencies or wavelengths that an electromagnetic radiation produces. This spectrum covers all of the EM frequencies that are composed of various portions, which bears different names in accordance with their practical applications and unique transmission, emission and absorption behaviors.
The range of the electromagnetic spectrum includes all gamma rays, ultraviolet radiation, X-rays, visible light, infrared radiation, and radio waves (radio, TV, radar, and microwave).
Spectroscopy is the scientific method used to separate the waves according to their different frequencies, which produces a spectrum that highlights the various frequency components that it contains.