15. A laser beam is incident at an angle of 30.0° from the
vertical onto a solution of corn syrup in water. If the beam is
refracted to 19.24° from the vertical, (a) what is the index
of refraction of the syrup solution? Suppose the light is red,
with vacuum wavelength 632.8 nm. Find its (b) wavelength,
(c) frequency, and (d) speed in the solution.