What is the electromagnetic spectrum?
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 10²⁵ hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus.
How the light affect the color we see?
All of the colors we see are a byproduct of spectrum light, as it is reflected off or absorbed into an object. An object that reflects back all of the rays of light will appear white; an object that absorbs all of the rays, black. All of the millions of other colors are produced by a combination of light rays being absorbed and reflected.