The<unk>  (EM)<unk>  is the range of all possible<unk>  radiation. The<unk> " (usually just<unk>  of an object is the characteristic distribution of<unk>  radiation from that object.
The<unk>  extends from below the frequencies used for modern radio (at the long-wavelength end) through gamma radiation (at the short-wavelength end), covering wavelengths from thousands of kilometres down to a fraction the size of an atom. It's thought that the short wavelength limit is the vicinity of the Planck length, and the long wavelength limit is the size of the universe itself (see physical cosmology), although in principle the<unk>  is infinite and continuous.
Electromagnetic spectrum
Absorption spectrum
Visible spectrum
Concussion classification
Mass versus weight
Spectroscopy
Extraction ratio
Octane rating