A ray of light is incident at an angle of `60^(@)` on the face of a prism having refracting angle `30^(@)`. The roy emerging out of the prism makes an angle `30^(@)` with the incident ray. Show that the emergert ray is perpendicular to the face through which, it emerges.

Explanation

According to given problem,
` A = 30^@ , i_1 = 60^@ and delta = 30^@`
and as in a prism ` delta = (i_1+i_2)-A `
` 30^@ = ( 60^@ +i_2) - 30^@`
` i.e., i_2 =0^@`
so thet emergent ray is
perpendicular to the face from which it emerges.
Now as `i_2 =0 ,r_2=0`
But as ` r_1 +r_2 =A ,r_1 = A=30^@`
so at first face ,1x sin `60^@ = mu sin 30^@ i.e., mu = sqrt(3)`