The infinite range of frequencies of electromagnetic radiation is called

Electromagnetic Spectrum

The electromagnetic spectrum is the infinite range of frequencies of electromagnetic radiation, but what does frequency have to do with electromagnetic radiation? Well, electromagnetic radiation travels in waves and frequency tells us how many cycles per second it has a particular wave. Another important term is wavelength  that measures the distance from one crest to the next in a wave. Although you can find waves having different frequency and wavelength, in vacuum, however, there is a relationship for all of them:

Where:

is the speed of light

is the wavelength

is the frequency

But what are those waves? Radio, Microwave, Infrared, Ultraviolet, X rays, Gamma rays and even visible light are part of the electromagnetic spectrum.

found in the nucleus

has mass of one amu

an electric circuit