Editing Wave (section)

=== Plane waves ===
{{Main|Plane wave}}

A [[plane wave]] is a kind of wave whose value varies only in one spatial direction. That is, its value is constant on a plane that is perpendicular to that direction. Plane waves can be specified by a vector of unit length <math>\hat n</math> indicating the direction that the wave varies in, and a wave profile describing how the wave varies as a function of the displacement along that direction (<math>\hat n \cdot \vec{x}</math>) and time (<math>t</math>). Since the wave profile only depends on the position <math>\vec{x}</math> in the combination <math>\hat n \cdot \vec{x}</math>, any displacement in directions perpendicular to <math>\hat n</math> cannot affect the value of the field.

Plane waves are often used to model [[electromagnetic waves]] far from a source. For electromagnetic plane waves, the electric and magnetic fields themselves are transverse to the direction of propagation, and also perpendicular to each other.