A light ray is incident on a glass sphere of reflective index `mu = sqrt3` at an angle of incidence `60^(@)` as shown in Fig. Find the angles r, `r^(')` e and the total deviation after two refractions.

Explanation

At point 'A' : Applying Snell's law
`1 sin 60^(@)=sqrt3 sin r rArr r=30^(@)`
From symmetry `r^'=r=30^(@)`.
Again applying Snell's law at second surface (at poing 'B')
`1sin e = sqrt3 sin r`.
`rArr e=60^(@)`
Deviation at the first surface, `delta_1=i-r=60^(@)-30^(@)=30^(@)`
Deviation at the second surface, `delta_2=e-r^(')=60^(@)-30^(@)=30^(@)`
Therefore, total deviation = `60^(@)`.