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.
A. `(sqrt(5))/(2)`
B. `(sqrt(5))/(sqrt(2))`
C. `(2sqrt(5))/(3)`
D. `(4)/(3)`