PASCO OS-8515C Basic Optics System - Manual (Page 32)

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B a s i c O p t i c s S y s t e m E x p e r i m e n t 1 1 : D i s p e r s i o n
32
the ray enters the lens through the curved surface, and the angle of incidence is
0°.
Procedure
1. Hold a piece of white paper vertically near the edge of the Ray Table so the out-
going ray is visible on the paper.
2. Slowly rotate the ray table to increase the angle of incidence. Notice that the ray
is refracted only at the flat surface of the lens, not at the curved surface. As you
continue to increase the angle of incidence, watch the refracted light on the paper.
Analysis
1. At what angle of refraction do you begin to notice color separation in the
refracted light?
2. At what angle of refraction does the maximum color separation occur?
3. What colors are present in the refracted ray? (Write them in the order of mini-
mum to maximum angle of refraction.)
4. Use Snell’s Law (Equation 11.1) to calculate the index of refraction of acrylic for
red light (n
red
) and the index of refraction for blue light (n
blue
).