Refraction of light ray

Question

A glass slab placed in air causes a beam of light to be displaced as it passes through it. If the slab is now placed in water, does the displacement of the beam increase, decrease or stay the same? Explain.

Answer 1

The displacement wil be less because of the comparitive ratios of the glass/air interface and the glass/water interface.

Hint: Snells Law.

Answer 2

Relative to the ray, it would be the same.  The glass hasn't changed.

Relative to you it could decrease, since the water will now have acted upon the ray as well.

Answer 3

the refraction should decrease as the ratio of the optical density of the water to the glass will be larger than the ratio of the optical density of air to glass