Final answer:
When the angle of incidence in glass exceeds the critical angle of 41.8°, the light experiences total internal reflection, being completely reflected back into the glass.
Step-by-step explanation:
The critical angle for a beam of light passing from glass into air is 41.8°. When the angle of incidence in the glass is greater than 41.8°, total internal reflection occurs. This means that all light rays with an angle of incidence greater than the critical angle will be completely reflected back into the glass. The critical angle is the angle of incidence that results in an angle of refraction of 90° when passing from a medium with a higher index of refraction to a medium with a lower index of refraction. Thus, for angles of incidence larger than the critical angle, refraction does not occur; instead, the light is confined within the glass medium.