Question

If the angle of incidence is at ${30}^{\circ }$. Find the angle of deflection, after reflecting 2 times.

• A. 270º
• B. 360º
• C. 240º
• D. 180º

Answer 1

The correct option is C

240º

Deviation at B = π - (2i)

= π - 2 (${30}^{\circ }$)

= π - ${60}^{\circ }$ = ${120}^{\circ }$

Deviation at A = π - 2i

= π - 2 (${30}^{\circ }$)

= ${120}^{\circ }$
Total deviation = ${240}^{\circ }$