The ratio of the velocity of light in a vacuum to that in a medium.
1Let me assume that the index of refraction in air is 1.
2The index of refraction of ebonite was found by Profs.
3Well, that won't give you the depth, but it could give you the index of refraction.
4You could also estimate the index of refraction by measuring the angular distance between the head and body.
5Their minds had the same index of refraction, so that thoughts flashed back and forth between them effortlessly and without distortion.
6Oh, let's say the index of refraction for water is 1.33 - that's important for the plot below.
Translations for index of refraction