Session 1, Page 6: Degree of Refraction


The angle which the incident ray makes with respect to the normal is referred to as the angle of incidence. Similarly, the angle which the refracted ray makes with respect to the normal is referred to as the angle of refraction. The angles of incidence and angles of refraction are denoted by the following symbols: q i = angle of incidence q r = angle of refraction

As Figure 9 illustrates, the degree of refraction of a light ray is dependent upon the density of the refracting medium. The density of a medium determines its refractive index. The refractive index, the ratio of the velocity of light in a vacuum to its velocity in the medium, indicates the extent to which light is refracted from a vacuum into the medium. A comparison of the angle of refraction to the angle of incidence provides a good measure of the refractive ability of any given boundary. For any given angle of incidence, the angle of refraction is dependent upon the speeds of light in each of the two materials; the speed is in turn dependent upon the optical density and the index of refraction values of the two materials.	$refraction6.gif (4238 bytes)$ Figure 9 Mediums of different density refract light to different amounts.

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