# Shared Flashcard Set

## Details

Light Concepts and Design
Optics and Light - Terminology
21
Physics
11/16/2012

Term
 Angle of Incidence
Definition
 The angle between the incident (incoming) light ray and the normal line.
Term
 Angle of Reflection
Definition
 The angle between the reflected (outgoing) light ray and the normal line.
Term
 Diffraction
Definition
 Diffraction is the bending of waves around obstacles, or the spreading of waves by passing them through an aperture, or opening.
Term
 Diffuse Reflection
Definition
 The reflection of light from an uneven or granular surface such that an incident ray is seemingly reflected at a number of angles.
Term
 Ellipsoidal Reflector
Definition
 A concave ellipsoidal surface used to focus rays from a light source at the near focal point onto the opposite focal point of the ellipse.
Term
 Focal Length
Definition
 The distance from the optical center to the principal foci.
Term
 Index of Refraction
Definition
 The speed of light in a vacuum divided by the speed of light in a medium; the ratio of the speed of light in a vacuum to the speed of light in any given medium.
Term
 Medium
Definition
 A material through which electromagnetic waves propagate.
Term
 Normal
Definition
 A line drawn perpendicular (at a right angle) to the reflective surface at the point of incidence.
Term
 Optical Axis
Definition
 A straight line that passes through the center of curvature on a lens and the principal focus point.
Term
 Optical Center
Definition
 The geometric center of a lens.
Term
 Optical Density
Definition
 The degree of opacity of a translucent medium expressed by log Io/I,where Io is the intensity of the incident ray and I is the intensity of the transmitted ray.
Term
 Parabolic Reflector
Definition
 A reflective surface generated by rotating a parabolic section aroundits axis. A light source placed at the focal point of the reflector will create areflected beam of concentrated collimated light parallel to the axis of the reflector.
Term
 Point of Incidence
Definition
 The spot where an incident ray strikes the surface of a mirror or lens.
Term
 Principal Foci
Definition
 A point where distant parallel light rays converge after passing through alens (Focus point).
Term
 Reflection
Definition
 The phenomenon of a propagating wave (light or sound) being thrown backfrom a surface.
Term
 Refraction
Definition
 The bending of light waves or rays as they go from one material to anotherdue to the differences in velocities in the material.
Term
 Selective Reflection
Definition
 Reflection from a colored surface so only certain wavelengths of light are reflected.
Term
 Spherical Reflector
Definition
 A reflector shaped like a portion of a sphere so that light from a point source at the center point of the sphere will be reflected back through the center point of the sphere.
Term
 Specular Reflection
Definition
 Light is reflected from a highly polished surface producing a consistent angle.
Term