How much does light refract at 90 degrees?

When light passes through a medium at a 90-degree angle, it does not refract; instead, it continues straight without changing direction. Refraction occurs when light enters a new medium at any angle other than 90 degrees, causing it to bend according to Snell's Law. Therefore, at 90 degrees, the angle of incidence equals the angle of refraction, resulting in no bending of light.