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Name: David A.
Status: educator
Age: 40s
Location: N/A
Country: N/A
Date: 3/26/2004

Is the critical angle for light going from air to water the same as the critical angle for light going from water to air?

David A.

A critical angle exists only for light passing from a slower-speed medium (high index of refraction) to a faster-speed medium (low index of refraction). When going from water to air, there is a critical angle: sine of the critical angle equals 1/1.33. When going from air to water, the sine of the critical angle would have to equal 1.33/1. Since a sine function cannot be greater than 1, there is no critical angle.

Dr. Ken Mellendorf
Physics Professor
Illinois Central College

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