Question

2. A light ray strikes a prism normally on face AB. What will be the
angles of incidence on faces AB and AC?​

Answer 1

Since the ray strikes normally at the surface AB, the angle of incidence for AB is 0° . The ray strikes surface AC. The angle between the ray and the surface AB is 30° (total internal angle of a triangle is 180° ) and hence the angle the ray makes with the normal to surface AC is 60° which is the angle of incidence.