Refraction of Light

Review these simulations before attempting this investigation:

The index of refraction of a medium, n, is the ratio of the speed of light in a vacuum, c, to its speed in the substance, v.

n = c/v

What happens when light enters a medium with a higher index of refraction than the medium it is leaving

(it bends toward the normal.)

What happens when light enters a medium with a lower index of refraction than the medium it is leaving

(it bends away from the normal.) This change of direction of light at the boundary of two media is called refraction.

For any light that is traveling from one medium of index of refraction n1, at angle of incidence θ1, to another medium of index of refraction n2, Snell’s law of refraction describes the angle of refraction, θ2, experienced by the light.

n1 sin θ1 = n2 sin θ2

For air, the index of refraction is equal to 1, because the speed of light in air is nearly equal to the speed of light in a vacuum. Whenever air is the medium of incidence of the light, Snell’s law can be simplified.

n2  = sin θ1/ sin θ2

In this lab, you will measure the angle of refraction of light in a glass slab for a number of different angles of incidence. You then will calculate the index of refraction of the glass. Finally, you will compare the index of refraction for each angle of incidence to verify that it is a constant.

 Procedure

Light Beam Through Glass Prism

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