Question

Two slabs with parallel faces are made from different types of glass. A ray of light travels through air and enters each slab at the same angle of incidence. Which slab has the greater index of refraction and why?

slab A is a light colored glass maybe transparent. The ray of light travel through the glass at the same angle it enters the glass.

slab B is of a darker color and the ray of light at initial entry is bent slightly downwards then at then at an angle.

Answer 1

The sine of the angle of refraction is related to the index of refracation. A has n=1, no bending. B bends it, so n>1

Answer 2

If a ray of light goes through the glass at the same angle it enters, as in the case of slab A, the index of refraction would be 1.00. There is no such glass, by the way. The color or darkness by itself has nothing to do with the index. It depends upon the composition.

Slab b, which bends the light downards, has the higher value of the index.