The refractive index of a material M1 changes by 0.014 and that of another material M2 changes by 0.024 as the color of the light is changed from red to violet. Two thin prisms, one made of M1(A=5.3°) and the other made of M2(A=3.7°) are combined with their refracting angles oppositely directed. A Find the angular dispersion produced by the combination. B The prisms are now combined with their refracting angles similarly directed. Find the angular dispersion produced by the combination.

Given that,


refractive index of a material M1 changes ==0.014


refractive index of a material M2 changes ==0.024


Prism angle of a material M1 = A1 = 5.30


Prism angle of a material M2 = A2 = 3.70


(a) When the prisms are oppositely directed,


angular dispersion =




(b) When they are similarly directed,


angular dispersion =




1