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Unformatted text preview: Refraction Effects Suppose, for ease of calculation, that we have a sample of a material with an index of refraction of exactly 2 , and we are observing the effects of shining a laser out of the material to the surrounding air ( n = 1 ) at various angles. As usual, a ray passing from a slower medium to a faster one (the air) bends away from the normal. When our incident angle θ within the material hits 30° , we notice something odd: Plugging the values we have into Snell’s law gives 1 sin θ ’ = 2 sin 30° , which means sin θ ’ = 1 or θ ’ = 90° . In other words, the angle of refraction has gotten so large that the ray fails to exit the medium, and it instead bounces of the interface as if the boundary with the air is a perfect mirror. For all angles above thirty degrees, the outgoing ray undergoes total internal reflection instead of going out. In general, the equation for calculating the critical angle θ c beyond which total internal reflection occurs between two transmissive materials is given by plugging in...
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This note was uploaded on 04/05/2012 for the course PHYS 131 taught by Professor Tibbets during the Spring '11 term at Cuyamaca College.
- Spring '11