Illustration of critical angle
- AOB AO'B' AO''B'' angles of incidence
- AOC refracted ray
- AO''C'' totally reflected ray
- AO'B' critical angle
critical angle
noun
: the least angle of incidence at which total reflection takes place
Examples of critical angle in a Sentence
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If light traveling through the core strikes the cladding within a certain critical angle, the slight difference in refractive indices between the two layers causes the beam to bend back into the core—a property called total internal reflection.
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IEEE Spectrum, 20 Mar. 2014
Likewise, in a second experiment, subjects were presented with the image of Kevin either gazing at the tube or gazing away in the opposite direction and asked to report the critical angle of the tube before toppling.
—Robert Martone, Scientific American, 29 Dec. 2020
The critical angle reported by subjects depended upon whether Kevin was blindfolded.
—Robert Martone, Scientific American, 29 Dec. 2020
As the airplane approaches that critical angle, the first event is a stall warning in the cockpit.
—New York Times, 18 Sep. 2019
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IEEE Spectrum, 20 Mar. 2014
Likewise, in a second experiment, subjects were presented with the image of Kevin either gazing at the tube or gazing away in the opposite direction and asked to report the critical angle of the tube before toppling.
—Robert Martone, Scientific American, 29 Dec. 2020
The critical angle reported by subjects depended upon whether Kevin was blindfolded.
—Robert Martone, Scientific American, 29 Dec. 2020
As the airplane approaches that critical angle, the first event is a stall warning in the cockpit.
—New York Times, 18 Sep. 2019
Cite this Entry
“Critical angle.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/critical%20angle. Accessed 29 Aug. 2025.
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