Law of reflection

The law of reflection states that an incident ray and a reflected ray make equal angles with the surface normal, and that both rays and the normal lie in one plane.

Angle of incidence: The angle between an incoming ray and the normal to a surface at the point of incidence. It is one of the two angles the law equates.
Geometric optics: An approximation that models light as rays traveling along definite paths. The law is a basic directional rule within this approximation.
Diffuse reflection: Reflection from a rough surface that scatters light in many directions. Unlike a smooth mirror, roughness redirects rays across many surface normals.
Plane mirror: A flat reflecting surface that forms an upright virtual image of an object. Its image location and orientation follow directly from equal reflection angles.
Angle of reflection: The angle between a reflected ray and the normal to a surface at the point of reflection. It is the outgoing angle matched to the angle of incidence.
Light ray: An idealized line showing the direction in which light energy propagates. Incident and reflected rays define the law's geometry.
Retroreflection: Reflection that sends incident light back toward its source. Corner-cube geometry reverses direction rather than producing ordinary mirror reflection.
Periscope: An optical instrument that uses mirrors or prisms to view along an offset line of sight. Its mirrors redirect light by repeated applications of the law.
Surface normal: A line perpendicular to a surface at a specified point. Both angles are measured from this reference line, not from the surface.
Wavefront: A surface joining points on a wave that share the same phase. Wavefront construction provides a geometric derivation of reflection.

Linked from 10 pages