The Electromagnetic spectrum is just a name for the range of ALL possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. The spectrum extends from below the low frequencies used for modern radio, to gamma radiation at the short-wavelength (or high-frequency) end, therefore covering wavelength for thousands of miles long down to wavelengths a fraction the size of atom. There is no set limit for the length of a wavelength so scientists define it as the size of the universe itself (which is pretty big…) while the short wavelength limit is in the vicinity of the Planck length (denoted ℓP, is a unit of length, equal to 1.616199(97)×10−35,) although in theory the spectrum is infinite and continuous. The Spectrum sits in an order such as; Radio Waves Microwaves Infra-Red Radiation VISABLE LIGHT Ultra-Violet X-Rays Gamma-Rays This order is specific to the frequency of the type of wave.
Something surrounds you, bombards you. Some of which you can't see, touch or even feel. Everyday, everywhere you go. It is odourless and tasteless. Yet you use it and depend on it everyday. Without it the world you know would not exist. What is it? Electromagnetic radiation. These waves spread across a spectrum,
From very short Gamma waves (10^-12 Meters)
To X-Rays (10^-10 Meters)
To Ultra-Violet waves (10^-8 Meters)
Then to Visible Light (10^-6 Meters)
Even longer Infra-Red waves (10^-5 Meters)
To larger again Microwaves (10^-2 Meters)
Until lastly Radio waves (10^2)...