A cylindrical glass of radius r=3 cm is full of salt water of height h=10 cm with the water's refraction index changing linearly from the bottom n1=1.401 to the top n2=1.400.
A flashlight is positioned so that light shines horizontally onto the glass. If we look at the light beams that pass through the center axis of the glass and out the other side, we notice that the outgoing ray (after it leaves the glass on the other side) is bent by a small angle with respect to the horizontal axis. Find the magnitude of that angle in degrees.
Details and assumptions
You may neglect any refraction in the actual glass itself. All the refraction happens in the water.