Refracting angle o f a prism `A=60^@` and its refractive index is `n=3//2`. What is angle of incidence i to get minimum deviation. Also, find the minimum deviation. Assume the surrounding medium to be air `(n=1)`.

Explanation

For minimum deviation:
`mu=(sin[(A+delta_(m))//2])/(sin(A//2))`
`(3)/(2)= (sin[(60^(@)+delta_(m))//2])/(sin(60^(@)//2))=sin((60+delta_(m))/(2))=(3)/(4)`
`rArr i=(A+delta_(m))/(2)=sin^(-1)((3)/(4))=48.5^(@)`