State Snell's law. Give its uses.
Snell's law states that the ratio of sine of angle of incidence (i) to the sine of angle of refraction (r) is a constant. This constant is called the refractive index of the material of the prism.
Thus, angle of incidence (i) and the angle of refraction (r) are related as
(sin i /sin r) = n21
where n21 is a constant, and is called the refractive index of the second medium with respect to the first medium.
Uses of Snell's law.
In the following two examples, use Snell's law, the sine button on your calculator, a protractor, and the index of refraction values to complete the following diagrams. Measure , calculate , and draw in the refracted ray with the calculated angle of refraction.
In each of these two example problems, the angle of refraction is the variable to be determined. The indices of refraction (ni and nr) are given and the angle of incidence can be measured. With three of the four variables known, substitution into Snell's law followed by algebraic manipulation will lead to the answer.
Thus, angle of incidence (i) and the angle of refraction (r) are related as
(sin i /sin r) = n21
where n21 is a constant, and is called the refractive index of the second medium with respect to the first medium.
Uses of Snell's law.
In the following two examples, use Snell's law, the sine button on your calculator, a protractor, and the index of refraction values to complete the following diagrams. Measure , calculate , and draw in the refracted ray with the calculated angle of refraction.
In each of these two example problems, the angle of refraction is the variable to be determined. The indices of refraction (ni and nr) are given and the angle of incidence can be measured. With three of the four variables known, substitution into Snell's law followed by algebraic manipulation will lead to the answer.
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