The term "electromagnetic Spectrum" (EMS) refers to a spectrum of wavelengths which consists of a wide range of electromagnetic radiation.

 

Visible light is one component/ type of electromagnetic radiation.

 

The energy of electromagnetic radiation is represented with the letter E. It is inversely proportional to the wavelength, λ

 

E ∝ 1/λ

 

Radiations with HIGH energy; gamma rays and X rays for example, tend to have small wavelengths.

 

In contrast to this, radiations with LOW energy; radio waves for example; tend to have longer wavelengths.

 

There is also an expression which links wavelength to frequency of the radiation, v:

 

C = Vλ

 

WHERE c is the speed of light (3.00 x 10^8 m^-1)

 

the Joule (J) is the SI unit for energy

The meter (m)  is the SI unit for the wavelength

The Hertz (Hz) is the Si unit for frequency