A double prism is made by joining two thin glass prisms of different refractive index such as crown glass and flint glass. It is conctructed to have unique property, there is no net deviation of the "D" Fraunhofer line when it goes though the combination of both prisms. The prism angle for the flint prism is 5°.
The refractive indices for the crown and flint glasses are Crown glass: n_c=1.527 n_d=1.530 and n_f=1.536 Flint glass: n_c=1.630 n_d=1.635 and n_f=1.648
a) Determine the prism angle of the crown prism
b) determine the net deviation of the "F" line for this combination of thin prisms.