The index of refraction for water is 1.33 and for glass it is 1.52. What happens to the speed of light when light travels from water into glass?

The speed of light decreases.

The speed of light in a medium is inversely proportional to the refractive index of the medium.

##v=frac{v_0}{n}##, where

##v## is the speed of light in a particular medium. ##v_0=3##x##10^8##m/s is the speed of light in vacuum, whose refractive index is 1. ##n## is the refractive index of the medium.

In water, the speed of light is ##frac{v_0}{1.33}=2.26##x##10^8##m/s.

In glass, the speed of light is ##frac{v_0}{1.52}=1.97##x##10^8##m/s.