What is the relationship between the angle of incidence and the angle of refraction when light passes through a boundary between two different mediums?

When light passes through a boundary between two different mediums, the angle of incidence (the angle at which the light enters the boundary) is related to the angle of refraction (the angle at which the light bends as it enters the second medium). This relationship is described by Snell's Law, which states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocities of light in the two mediums.