A parallel beam of light falls normally on the first face of a prism of small angle .At the second face it is partly reflected,the reflected beam striking at the first face again, and emerging from it in a direction making an angle `6^(@)` 30' with the reversed direction of the incident beam. The refracted beam is found to have undergone a deviation of `1^@ 15'` from the original direction.Find the refractive index of the glass and the angle of the prism.

Answer

`mu=(13)/(8),A=2^(@)`

Explanation

`delta=(mu-1)A rArr 1.25=(mu-1)A…(1)`
`1 sin 6.5=musin2A rArr 6.5=muxx2A rArr 3.25=muA….(2)`
From (1)and(2) `1.25=3.25-A rArrA=2 rArr1.25=(mu-1)2`
`(5)/(4)=(mu-1)2 rArr (mu-1)=(5)/(8)`
`mu=(13)/(8)`