Question

The refractive index of a medium changes with the wavelength of incident light. Typically, the shorter the wavelength the larger the refractive index.

Fused quartz has a refractive index of 1.47 for indigo light of 400 nm in wavelength, and a refractive index of 1.46 for green light of 550 nm in wavelength.

If rays of indigo and green light enter fused quartz from air, making an angle of 45º, the angle that separates two rays as they travel through the fused quartz is closest to ...

43.2º
42.9º
29.0º
28.8º
0.37º
0.22º

Test on monday. Help please

Answer 1

Both rays bend by nearly the same amount, so the answer will be one of the smaller numbers.

The angle of refraction (measured from the normal to the surface) is given by

sin Ar = sin Ai/N, where Ai is the angle if incidence (45 degrees in this case)

For the indigo ray,
sin Ar = 0.4810 Ar = 28.75 degrees
For the green ray
sin Ar = 0.4843 Ar = 28.97 degrees

Take the difference