A ray of green light travels through air and is refracted as it enters a glass prism shown in the figure. An unknown liquid is in contact with the right side of the prism. The light then follows the path shown. Which one of the following statements concerning this situation is true?
a. The index of refraction of the unknown liquid is the same as that of the glass.
b. The frequency of the light changes inside the prism.
c. The index of refraction of the glass is smaller than that of air.
d. The speed of light is larger in the liquid than in the glass.
e. The refractive index of the liquid is the same as that of air.
