Editing Wave (section)

== Electromagnetic waves ==
[[File:Onde electromagnétique.png|class=skin-invert-image|thumb|right|300 px]]

{{Main|Electromagnetic wave}}
{{Further|Electromagnetic spectrum}}

An electromagnetic wave consists of two waves that are oscillations of the [[electric field|electric]] and [[magnetic field|magnetic]] fields. An electromagnetic wave travels in a direction that is at right angles to the oscillation direction of both fields. In the 19th century, [[James Clerk Maxwell]] showed that, in [[vacuum]], the electric and magnetic fields satisfy the [[wave equation]] both with speed equal to that of the [[speed of light]]. From this emerged the idea that [[visible light|light]] is an electromagnetic wave. The unification of light and electromagnetic waves was experimentally confirmed by [[Heinrich Hertz|Hertz]] in the end of the 1880s. Electromagnetic waves can have different frequencies (and thus wavelengths), and are classified accordingly in wavebands, such as [[radio waves]], [[microwaves]], [[infrared]], [[visible light]], [[ultraviolet]], [[X-rays]], and [[gamma ray]]s. The range of frequencies in each of these bands is continuous, and the limits of each band are mostly arbitrary, with the exception of visible light, which must be visible to the normal human eye.