Question

Two mirrors are arranged as shown in the figure. Light is incident on the first mirror at an angle of ${35}^o$. The light reflects towards a second mirror. Determine that angle $\theta indegrees$.

Answer 1

Given: Two mirrors are arranged as shown in the figure. Light is incident on the first mirror at an angle of ${35}^{\circ }$. The light reflects towards a second mirror.

To find: the angle $\theta$

Solution:

From the above figure, angle of incidence of the first light ray is ${35}^{\circ }$.

Hence the angle between the first incident ray the mirror is $({90}^{\circ }-{35}^{\circ })$ i.e., ${55}^{\circ }$

By observation $OAB$ forms a triangle,

$\angle A=55+35+35={125}^{\circ }$

Hence, For the triangle, $40+125+\theta ={180}^{\circ }$

$⟹\theta ={15}^{\circ }$