For a prism, `A=60^(@), n=sqrt(7//3)` . Find the minimum possible angle of incidence, so that the light ray is refracted from the second surface. Also, find `delta_(max)`.

Explanation

In minimum incidence case the angles will be as shown in figure
Applying snell’s law :
`1xx sin i_("sin")=sqrt(7/3) sin (A-C)`
`=sqrt(7/3) (sin A cos C-cos A sin C)`

`=sqrt(7/3) (sin 60 sqrt(1-3/7)-cos 60sqrt(3/7))=1/2`
`:. i_("min")=30^(@)`
`:. delta_("max")=i_("min")+90^(@)-A`
`=30^(@)+90^(@)-60^(@)=60^(@)`