Editing Reflection (physics) (section)

{{Short description|"Bouncing back" of waves at an interface}}
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[[File:Mount Hood reflected in Mirror Lake, Oregon.jpg|thumb|The reflection of [[Mount Hood]] in [[Mirror Lake (Mount Hood, Oregon)|Mirror Lake]]]]
'''Reflection''' is the change in direction of a [[wavefront]] at an [[Interface (matter)|interface]] between two different [[medium (optics)|media]] so that the wavefront returns into the medium from which it originated. Common examples include the reflection of [[light]], [[sound]] and [[water wave]]s. The ''law of reflection'' says that for [[specular reflection]] (for example at a [[mirror]]) the angle at which the wave is incident on the surface equals the angle at which it is reflected.

In [[acoustics]], reflection causes [[Echo (phenomenon)|echoes]] and is used in [[sonar]]. In geology, it is important in the study of [[seismic wave]]s. Reflection is observed with [[surface wave]]s in bodies of water. Reflection is observed with many types of [[electromagnetic wave]], besides [[visible light]]. Reflection of [[Very high frequency|VHF]] and higher frequencies is important for [[radio]] transmission and for [[radar]]. Even [[hard X-ray]]s and [[gamma ray]]s can be reflected at shallow angles with special "grazing" mirrors.