Question

Two plane mirrors are arranged as shown in the figure. A ray has been incident on one of the mirrors at an angle of ${40}^{\circ }$. The deviations produced in the incident ray after three successive reflections will be

• A. ${40}^{\circ }$ clockwise
• B. ${40}^{\circ }$ anticlockwise
• C. ${140}^{\circ }$ anticlockwise
• D. ${140}^{\circ }$ clockwise

Answer 1

The correct option is D ${140}^{\circ }$ clockwise


From the figure, we can see that after third reflection, the ray become perpendicular to the surface of the mirror $M_1$.
On finding all the required angles as shown in the figure, we can see that, the ray get deviated by ${140}^{\circ }$ clockwise.