critical angle
- noun
- /ˈkrɪtɪkəl ˈeɪŋɡəl/
- Specialized
:
ángulo crítico
- And when you go past a certain angle, a critical angle, you will have total internal reflection.
Examples
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The critical angle for water is approximately 49 degrees, where total internal reflection occurs.
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Shining X-rays onto a surface at close to the critical angle of total reflection and detecting the specularly reflected intensity yields a wealth of information.
Academic text (1995) -
That interface has a critical angle? Typically about 15, depending on the material there.
Academic text (2004) -
As I approach the critical angle, the beam should whoop too much.
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Now we're ready to look at the state of polarization of the reflected beam after the critical angle or the totally internal reflected beam.
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But at a certain critical angle, this means a deflection, Beth Latimer, which is so large that the beam does not penetrate.
Blog text (20) -
And that spatial dependence, in turn, is related to the critical angle associated with the waveguide (see box 2) and attenuation of the signal.
Academic text (2004) -
The large-angle rays, however, may be at angles greater than the critical angle for exiting the high-index glass at the base of the SIL.
Academic text (1995) -
When light hits the boundary at the critical angle, it is completely reflected instead of passing through.
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Understanding the critical angle is essential for optimizing the performance of optical fibers.
Surface Forms
Morphology
The parts 'critical' (a threshold or decisive point) and 'angle' (a measure between lines) give a partial, compositional clue — it denotes some important or threshold angle. However, the precise technical sense (the smallest incidence angle producing total internal reflection) requires specific physics knowledge and is not derivable by a B1 learner who only knows the basic word meanings. Therefore the phrase is partially transparent but not fully predictable without subject exposure.
Etymology
The term critical angle comes from a simple picture: imagine a beam of light inside water hitting the surface at a certain angle. When the beam hits at a small tilt it passes through, but at the special critical tilt the light is completely reflected back, so the term marks the smallest angle when light is 'totally reflected'.
