Introduction

Electromagnetic spectrum:

    It is  range of frequencies of electromagnetic radiation and their corresponding wavelengths and energy of the photon. 

Fig. Electromagnetic spectrum

It covers electromagnetic waves within the frequency range from below 1 Hz to 10^25Hz and it corresponds to wavelengths from thousands of km down to a fraction of size of atomic nucleus. 

The range of frequency is divided into various bands and each of having different names:
I) Radio waves
II) Microwaves
III) Infrared
IV) Visible light
V) UV Light
VI) X- Rays
VII) Gamma Rays

Each of these bands or waves have different properties and characteristics, in respect to origin, interaction, and their applications. 

All the above waves can be seprated physically by a technique called spectroscopy.