A ray of light is incident at an angle of `60^@` on the face of a prism having refracting angle `30^@.` The ray emerging out of the prism makes an angle `30^@` with the incident ray. Show that the emergent ray is perpendicular to the face through which it emerges and calculate the refractive index of the material of prism.

Explanation

Given, `i_(1)=60^(@),A=30^(@)and delta=30^(@)`
From the relation, `delta=(i_(1)+i_(2))-A`
we have, `i_(2)`=0
This means that the emergent ray is perpendicu,ar to the face through which it emerges.