An equilateral prism ABC is placed in air with its base side BC lying horizontally along x-axis. A light ray is incident at a point P on face AB of the prism.
If for the prism is , then net deviation of the ray as it emerges out of the prism is
For total internal reflection takes place at AC. From geometry, it in clear that ray
in perpendicular incident on BC, so net deviation = only at AC.