Electromagnetic spectrum

The electromagnetic spectrum is the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies. Frequencies range from below one hertz to above 1025 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of an atomic nucleus, with the limit around the Planck length. The higher the frequency, the shorter the wavelength.

Photon energy is the energy carried by a single photon. The photon is a particle (boson) that is the quantum of the electromagnetic spectrum, and the force carrier for the electromagnetic force. Photons are massless, so they always move at the speed of light in vacuum.

The types of electromagnetic radiation are broadly classified into the following classes: