critical angle
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critical angle
n.
- 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.
- The angle of attack of an airfoil at which airflow abruptly changes, causing changes in the lift and drag of an aircraft.
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critical angle
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critical angle
In an optical fiber, the maximum angle from the axis at which light can remain confined within the core for "total internal reflection." In contrast to the "acceptance angle," which is measured outside the fiber, the critical angle is a measurement within the fiber. See numerical aperture.
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McGraw-Hill Dictionary of Architecture & Construction:
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critical angle
An angle of pitch of stairs or a ramp which is considered uncomfortable and unsafe if exceeded; this angle is 50° for stairs and 20° for ramps.
McGraw-Hill Dictionary of Aviation:
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critical angle
i. The minimum angle of incidence at which a radio wave of a particular frequency can strike the ionosphere and still be reflected back to the earth. Critical angle is a function of frequency; the higher the frequency, the larger the critical angle.
If radio wave hits the ionosphere at an angle higher than critical angle, it would not be reflected back, but will pass through the ionosphere into space.
ii. The angle of attack of an airfoil at which the flow of air about the airfoil changes abruptly in such a manner that the lift is sharply reduced and the drag is sharply increased. Sometimes called stalling angle of attack.
iii. The angle at which a reflected ray of light when transmitted from a denser to a rarer medium is bent so far from the normal that it does not enter the rarer medium at all but travels parallel to the surface between the media.
iv. The angle of bank beyond which a helicopter resting on the ground on one skid or one wheel is likely to roll over in an uncontrolled manner.
At the instant of rollover of a helicopter, a moment is produced by the horizontal component of total rotor thrust about the point of ground contact of the skid. This moment is opposed by weight of the aircraft. If the angle of bank is beyond the critical angle the restoring moment is too small to stop the helicopter from rolling over.
ii. The angle of attack of an airfoil at which the flow of air about the airfoil changes abruptly in such a manner that the lift is sharply reduced and the drag is sharply increased. Sometimes called stalling angle of attack.
iii. The angle at which a reflected ray of light when transmitted from a denser to a rarer medium is bent so far from the normal that it does not enter the rarer medium at all but travels parallel to the surface between the media.
iv. The angle of bank beyond which a helicopter resting on the ground on one skid or one wheel is likely to roll over in an uncontrolled manner.
Oxford Dictionary of Biochemistry:
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critical angle
symbol: C; the least angle of incidence at which total internal reflection of a ray of light or other electromagnetic radiation occurs when passing through a medium and meeting the boundary with a medium of lesser density (e.g. of glass with air).
| crista, crinophagy, cretinism | |
| critical assessment competition, critical electrolyte concentration, critical micellar concentration |
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categories related to 'critical angle'
- Optics - critical angle: minimum angle of incidence that produces total internal reflection
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American Heritage Dictionary
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
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Computer Desktop Encyclopedia
THIS DEFINITION IS FOR PERSONAL USE ONLY.
All other reproduction is strictly prohibited without permission from the publisher.
© 1981-2012 The Computer Language Company Inc. All rights reserved. Read more
All other reproduction is strictly prohibited without permission from the publisher.
© 1981-2012 The Computer Language Company Inc. All rights reserved. Read more
McGraw-Hill Dictionary of Architecture & Construction
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc. All rights reserved.
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McGraw-Hill Dictionary of Aviation
An Illustrated Dictionary of Aviation.. Copyright © 2005 by McGraw-Hill Companies, Inc. All rights reserved.
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Oxford Dictionary of Biochemistry
Oxford University Press. Oxford Dictionary of Biochemistry and Molecular Biology © 1997, 2000, 2006 All rights reserved.
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Mentioned in
critical angle refractometer
(optics)
total internal reflection
(technology)
neutron reflection
(physics)
Pulfrich refractometer
(optics)
stall warning indicator
(aerospace engineering)
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