In the figure given below, a ray of light PQ is incident normally on the face AB of an equilateral glass prism. Complete the ray diagram showing its emergence into air after passing through the prism. Take critical angle for glass = 42°

(a) Write the angles of incidence at the faces AB and AC of the prism.
(b) Name the phenomenon suffered by the ray of light at the face AB, AC and BC of the prism respectively.
Below is the completed diagram showing the path of the light ray till it emerges out of the prism with all angles marked:

(a)
Angle of incidence at face AB = 90°
Angle of incidence at face AC = 60°
Angle of incidence at face BC = 90°
(b)
At face AB and AC — The ray of light passes undeviated
At face BC — The ray of light suffers total internal reflection