Editing Electromagnetic spectrum (section)

{{short description|Range of frequencies or wavelengths of electromagnetic radiation}}
[[File:EM Spectrum Properties edit.svg|thumb|330px|A diagram of the electromagnetic spectrum, showing various properties across the range of frequencies and wavelengths]]

The '''electromagnetic spectrum''' is the full range of [[electromagnetic radiation]], organized by [[frequency]] or [[wavelength]]. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high frequency these are: [[radio wave]]s, [[microwave]]s, [[infrared]], [[visible light]], [[ultraviolet]], [[X-ray]]s, and [[gamma ray]]s. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications.

Radio waves, at the low-frequency end of the spectrum, have the lowest [[photon energy]] and the longest wavelengths—thousands of [[kilometer]]s, or more. They can be emitted and received by [[antenna (radio)|antenna]]s, and pass through the atmosphere, foliage, and most building materials.

Gamma rays, at the high-frequency end of the spectrum, have the highest photon energies and the shortest wavelengths—much smaller than an [[atomic nucleus]]. Gamma rays, X-rays, and extreme ultraviolet rays are called [[ionizing radiation]] because their high photon energy is able to  [[Ionization|ionize]] atoms, causing chemical reactions. Longer-wavelength radiation such as visible light is nonionizing; the photons do not have sufficient energy to ionize atoms.

Throughout most of the electromagnetic spectrum, [[spectroscopy]] can be used to separate waves of different frequencies, so that the intensity of the radiation can be measured as a function of frequency or wavelength. Spectroscopy is used to study the interactions of electromagnetic waves with matter.<ref name="em-spectrum">{{cite web|last=Mehta |first=Akul |url=http://pharmaxchange.info/press/2011/08/introduction-to-the-electromagnetic-spectrum-and-spectroscopy/ |title=Introduction to the Electromagnetic Spectrum and Spectroscopy |date=25 August 2011 |publisher=Pharmaxchange.info |access-date=2011-11-08}}</ref>