Question

Analyze the ray diagram of two mirrors inclined at an angle to each other. Find the angle between two mirrors?

• A. ${30}^{\circ }$
• B. ${90}^{\circ }$
• C. ${60}^{\circ }$
• D. ${75}^{\circ }$

Answer 1

The correct option is C ${60}^{\circ }$

Given:
Angle between the two mirror is $\theta$
Angle of incidence for the tilted mirror is $i_1={90}^{\circ }-\theta$
Angle of reflection for the horizontal mirror is $r_2={90}^{\circ }-\theta$

According to the law of reflection, angle of incidence is equal to the angle of reflection. Applying the above property along with the complementary angles property, we get all the angles inside the triangle as $\theta$.
Using the angle sum property,
$\theta +\theta +\theta ={180}^{\circ }$
$\theta ={60}^{\circ }$