Figure 33-31 shows the multiple reflections of a light ray along a glass corridor where the walls are either parallel or perpendicular to one another. If the angle of incidence at point a is$\mathbf{30}\mathbf{°}$, what are the angles of reflection of the light ray at points b, c, d, e, and f?

Figure 33-31 showing multiple reflections of a light ray through the glass corridor is given.

The angle of incidence at a,$\angle i=30°$

The law of reflection states that the angle of incidence is equal to the angle of reflection at the point of incidence of the normal line. Thus, by analyzing the given figure and using the law of reflection and the properties of angles made by parallel lines, we can find the angles of reflection of the light at b, c, d, e, and f.

Formula:

The law of reflection states that the incidence angle is equal to the reflected angle,

$\angle i=\angle r$ (i)

Let’s draw a normal to surfaces.

Using equation (i) and the properties of angles made by parallel lines, we can show the angles made by the incident and reflected rays with normal at different points as below.

Therefore, the angles of reflection of the light at b, c, d, e and f are, $30°,60°,60°,30°\text{and}60°$respectively.