critical angle

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critical angle

1. The smallest angle of incidence at which a light ray passing from one medium to another less refractive medium can be totally reflected from the boundary between the two.
2. The angle of attack of an airfoil at which airflow abruptly changes, causing changes in the lift and drag of an aircraft.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

critical angle

1. (General Physics) the smallest possible angle of incidence for which light rays are totally reflected at an interface between substances of different refractive index
2. (Aeronautics) another name for stalling angle
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

crit′ical an′gle

1. 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.
2. the angle of attack at which a sudden change in airflow occurs around the wings of an aircraft, reducing lift and increasing drag.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.

crit·i·cal angle

The smallest angle of incidence at which a light ray can be completely reflected from the boundary between two media.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.critical angle - the smallest angle of incidence for which light is totally reflected
angle of incidence, incidence angle - the angle that a line makes with a line perpendicular to the surface at the point of incidence
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Defining the critical angle as the value above which no opening mode appears, the critical angle is around 30[degrees] for [[sigma].sub.0] = 0.8[z.sub.p][A.sub.i], 54[degrees] for [[sigma].sub.0] = 0.6[z.sub.p][A.sub.i], 81[degrees] for [[sigma].sub.0] = 0.4[z.sub.p][A.sub.i], and 87[degrees] for [[sigma].sub.0] = 0.2[z.sub.p][A.sub.i].
The selected angles above the critical angle ac allowed the X-rays to penetrate through the capping layer and deep enough into the film.
'Looking at another critical angle, if we examine the supplies needed in the coming years, we must meet not only demand growth, but also make up the natural decline of legacy fields,' he said.
The critical angle that the front face sheet cannot be penetrated was 87[degrees] as shown in Figure 8(a).
But it's a critical angle that activists need to develop.
This is because light that enters or leaves the water within the "critical angle" of 48.6[degrees] will be refracted and can be seen underwater, while outside of the critical angle, it will be reflected away.
The incidence angle was set at [[alpha].sub.i] = 0.13[degrees] which is higher than the critical angle of the PTB7:P[C.sub.71]BM blend film but lower than that of the glass substrate to bring out any weak signals from the sprayed film.
Total internal reflection (TIR) is an optical phenomenon when light travels from material (medium) with lower optical density to a secondary material (medium) with higher optical density at a light incidence angle greater than specific critical angle, then refraction becomes equal to 90[degrees] and theoretically all light energy is reflected at the boundary surface, none is transmitted:
There seems to be a critical angle of incidence determining whether a bullet dives down into the water or bounces off into the stratosphere.
The angle of incidence that yields an angle of refraction of 90[degrees] is the critical angle. If the angle of incidence increases more than the critical angle, the light is totally reflected back into the first material so that it does not enter the second material.
If you get it just right, the light will hit the boundary at a critical angle and will bounce back without exiting the jelly.

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