What do a.m. and p.m. stand for?

critical angle

Optics. the minimum angle of incidence beyond which total internal reflection occurs for light traveling from a medium of higher to one of lower index of refraction; the angle of incidence for which refracted rays emerge tangent to the surface separating two media, the light traveling from the medium of higher to the medium of lower index of refraction.
Also called angle of stall, critical angle of attack, stalling angle. Aeronautics. the angle of attack, greater than or equal to the angle of attack for maximum lift, at which there is a sudden change in the airflow around an airfoil with a subsequent decrease in lift and increase in drag.
Origin of critical angle
1870-75 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source
Examples from the web for critical angle
  • However, for low energy the channeling critical angle becomes much larger so that the actual situation needs detailed study.
  • What is measured is the profile of reflectivity as a function of angle beyond the critical angle for total external reflection.
  • The microstructure that can be seen above the critical angle, the left image, indicates that the sample is strained.
  • The lower limit is due to the x-ray windows and the upper limit is due to the critical angle of the x-ray mirror.
  • The speed at which the critical angle of the relative wind is exceeded is the stall speed.
British Dictionary definitions for critical angle

critical angle

the smallest possible angle of incidence for which light rays are totally reflected at an interface between substances of different refractive index
another name for stalling angle
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
critical angle in Science
critical angle
The smallest angle of incidence at which radiation, such as light, is completely reflected from the boundary between two media. At angles smaller than the critical angle, some of the radiation enters the second material and is refracted.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source

Word of the Day

Difficulty index for critical angle

Few English speakers likely know this word

Word Value for critical

Scrabble Words With Friends