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

The correct option is C

240º

Deviation at B = $\pi$ - 2i

= $\pi$ - 2 (${30}^{\circ }$)

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

Deviation at A = $\pi$ - 2i

= $\pi$ - 2 (${30}^{\circ }$)

= ${120}^{\circ }$

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