Changes

== Physical Reflection==

== Physical Reflection==

Reflections may occur in a number of wave and particle phenomena; these include [[acoustics|acoustic]] (as in common echos and underwater [[sonar]]), seismic waves in geologic structures, surface waves in bodies of water, and various electromagnetic waves, most usefully from [[Very high frequency|VHF]] and higher radar frequencies, progressing upward through centimeter to millimeter-wavelength [[radar]] and the various [[light]] frequencies and (with special "grazing" mirrors, to [[X-ray]] frequencies and beyond to [[gamma ray]]s.

Reflections may occur in a number of wave and particle phenomena; these include [[acoustics|acoustic]] (as in common echos and underwater [[sonar]]), seismic waves in geologic structures, surface waves in bodies of water, and various electromagnetic waves, most usefully from [[Very high frequency|VHF]] and higher radar frequencies, progressing upward through centimeter to millimeter-wavelength [[radar]] and the various [[light]] frequencies and (with special "grazing" mirrors, to [[X-ray]] frequencies and beyond to [[gamma ray]]s.

 

===Reflection of light===

===Reflection of light===

Reflection of light may be ''specular'' (that is, mirror-like) or ''diffuse'' (that is, not retaining the image, only the [[energy]]) depending on the nature of the interface. Furthermore, if the interface is between dielectric-conductor or dielectric-dielectric media, the phase of the reflected wave may or may not be inverted, respectively.

Reflection of light may be ''specular'' (that is, mirror-like) or ''diffuse'' (that is, not retaining the image, only the [[energy]]) depending on the nature of the interface. Furthermore, if the interface is between dielectric-conductor or dielectric-dielectric media, the phase of the reflected wave may or may not be inverted, respectively.

Light waves incident on a material induce small oscillations of polarisation in the individual atoms, causing each atom to radiate a weak secondary wave (in all directions like a dipole antenna). All of these waves add up to specular reflection and refraction.

Light waves incident on a material induce small oscillations of polarisation in the individual atoms, causing each atom to radiate a weak secondary wave (in all directions like a dipole antenna). All of these waves add up to specular reflection and refraction.

Light–matter interaction in terms of photons is a topic of [[quantum electrodynamics]], and is described in detail by [[Richard Feynman]] in his popular book ''QED: The Strange Theory of Light and Matter''.

Light–matter interaction in terms of photons is a topic of [[quantum electrodynamics]], and is described in detail by [[Richard Feynman]] in his popular book ''QED: The Strange Theory of Light and Matter''.

==Mindal Reflection==

==Mindal Reflection==

===Introspection===

===Introspection===