A ray of light is inclined to one face of a prism at an angle of `60^@`. If angle of prism is `60^@` and the ray deviated through an angle of `42^@` find the angle which the emergent ray makes with second face of the prism.

Answer

`18^(@)`

Explanation

Here, `i_(1) = 90^(@) - 60^(@) = 30^(@), A = 60^(@)`,
`delta = 42^(@) , (90 - i_(2)) = ?`
Use `i_(1) + i_(2) = A + delta`
Remember that `i_(1), i_(2)` are angles with normal to the faces of the prism.