A flint glass prism and a crown glass prism are to be combined in such a way that the deviation of the mean ray is zero. The refractive index of flint and crown glasses for the mean ray are 1.620 and 1.518 respectively. If the refracting angle of the flint prism is `6.0^@`, what would be the refracting angle of the crown prism ?

Answer

`4^(@)`

Explanation

Since deviation of mean ray is zero.
`A(mu_(m1)-1) = A_(2) (mu_(m2) - 1)`
`6^(@) (1.6-1) = A_(2) (1.9 - 1)`
`A_(2) = (6^(@) xx 0.6)/(0.9) = 4^(@)`