question_answer 21)

At what angle should a ray of light be incidenton the face of a prism of refracting angle 60°so that it just suffers total internal reflectionat the other face? The refractive index of the material of the prism is 1.524. 

Answer:

Let the ray of light be incident on the face AB at angle i so that it is totally internallyreflected at face AC. Then the critical angle is given by for total internal reflection using using or