Editing Reflection coefficient (section)

{{Short description|Measure of wave reflectivity}}
{{About|reflections of waves|the use of the term with capillary membrames|Starling equation#Reflection coefficient|intensity ratios|Reflectance}}

{{More footnotes|date=October 2024}}
In [[physics]] and [[electrical engineering]] the '''reflection coefficient''' is a parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium.  It is equal to the ratio of the [[amplitude]] of the reflected wave to the incident wave, with each expressed as [[phasor]]s.  For example, it is used in [[optics]] to calculate the amount of light that is reflected from a surface with a different index of refraction, such as a glass surface, or in an electrical [[transmission line]] to calculate how much of the [[Reflections of signals on conducting lines|electromagnetic wave]] is reflected by an impedance discontinuity. The reflection coefficient is closely related to the ''[[transmission coefficient]]''. The [[reflectance]] of a system is also sometimes called a reflection coefficient.

[[Image:Partial transmittance.gif|right|frame|A wave is partially transmitted and partially reflected when the medium through which it travels suddenly changes.  The reflection coefficient determines the ratio of the reflected wave amplitude to the incident wave amplitude.]]

Different disciplines have different applications for the term.