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Critical angle
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At some particular value of iGLASS, iAIR reaches 90°.

Definitions

This angle, iGLASSc, is called the critical angle for the glass-air surface.

From Snell's law we get

sin iGLASSc / sin 90° = 1 / AIRnGLASS
sin iGLASSc = 1 / AIRnGLASS
iGLASSc = sin-1 (1 / AIRnGLASS)

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questions.gif (805 bytes)

Calculate the value of iGLASSc, given that iGLASS = 1.50.

41.81°
45°
48.75°
90°

 

What would be the value of the critical angle for a water-air surface, given that   iWATER = 1.33?

41.81°
45°
48.75°
90°
 

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