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

`i=60^@`, `A=30^@`, `delta=30^@`
`delta=(i+i^')-A`
`30=60+i^'-30`
`i^'=0^@`

`1xxsin60^@=musinA=musin30^@`
`sqrt3/2=muxx1/2`
`mu=sqrt3`