A ray of light is incident on a face of equilateral triangle at an incident angle 50. At this angle minimum deviation occurs. This deviation is

30 40 50 None of these

40

A = 60° At minimum deviation: i = e = 50° Also, $r_1=r_2=\frac{A}{2}$ = 30° $\delta_{\min }$ = i + e - A = 100° - 60° = 40°