Chapter 14.2, Problem 1E

To determine

To write the measures of angles that the initial light ray and the reflected light rays make with the mirrors in the diagram of the periscope.

Answer to Problem 1E

The initial light ray and reflected light ray both makes an angle of $45°$ with the mirror.

Explanation of Solution

Given information:

It is given in the description of diagram that the mirrors makes an angle of $45°$ with the horizontal.

Since the initial ray is parallel to the horizontal and the mirror makes an angle of $45°$ with the horizontal hence, the angle made by the initial light ray with mirror is equal to $45°$ .

Angle made by the initial ray with the normal of mirror is

$90°-45°=45°$

According to law of reflection reflected ray makes the same angle with the normal of incidence surface as the angle made by the incident ray with the normal of incidence surface. Hence, reflected light ray makes an angle of $45°$ with the normal of the mirror.

Now the angle made by the reflected light ray with the mirror is

$90°-45°=45°$

Therefore,

The initial light ray and reflected light ray both makes an angle of $45°$ with the mirror.