critical angle


Definition of critical angle

: the least angle of incidence at which total reflection takes place

Illustration of critical angle

Illustration of critical angle

critical angle: AOB, AO'B', AO''B'' angles of incidence; AOC refracted ray; AO''C'' totally reflected ray; AO'B' critical angle

Examples of critical angle in a Sentence

Recent Examples on the Web As the airplane approaches that critical angle, the first event is a stall warning in the cockpit. New York Times, "What Really Brought Down the Boeing 737 Max?," 18 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'critical angle.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of critical angle

1873, in the meaning defined above

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Time Traveler for critical angle

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The first known use of critical angle was in 1873

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Cite this Entry

“Critical angle.” Dictionary, Merriam-Webster, Accessed 15 Aug. 2020.

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