Which is true of the phenomenon of refraction: a) it concerns the change in the path of light rays as they go from one medium to another b) it can be described mathematically by Snell's Law c) it concerns the change of the speed of light as it goes from one medium to another d) all of the answers are correct.

To understand the refraction of light rays passing through a thin converging

lens:

a) rays are considered to have refracted at the mid-line of the lens

b) ray entering the lens through the focal point, exits the lens parallel to the symmetry axis

c) ray entering the lens parallel to the symmetry axis, exits the lens through the focal point

d) all of the answers are correct