Question

Solve the following examples.
a. If the angle between the plane mirror and the incident ray is 40^∘, what are the angles of incidence and reflection?
b. If the angle between the mirror and reflected ray is 23^∘, what is the angle of incidence of the incidence ray?

Answer 1

a.

$$\begin{gathered} \angle i+{40}^{\mathrm{o}}={90}^{\mathrm{o}} \\ \Rightarrow \angle i={50}^{\mathrm{o}} \\ \mathrm{Using}\mathrm{law}\mathrm{of}\mathrm{reflection},\mathrm{we}\mathrm{have} \\ \angle i=\angle r={50}^{\mathrm{o}} \end{gathered}$$

b.

$$\begin{gathered} \angle r+{23}^{\mathrm{o}}={90}^{\mathrm{o}} \\ \Rightarrow \angle r={67}^{\mathrm{o}} \\ \mathrm{Using}\mathrm{law}\mathrm{of}\mathrm{reflection},\mathrm{we}\mathrm{have} \\ \angle i=\angle r={67}^{\mathrm{o}} \end{gathered}$$