Question

A crown glass prism and a flint glass prism are combined to produce dispersion without deviation. Mean refractive indices of crown and flint glass are respectively 1.5 and 1.6. Ratio of angle of crown glass prism to that of flint prism is

• A. 1.06
• B. 0.9375
• C. 1.2
• D. 1.5

Answer 1

Answer: (C)

1.2

For the ray to pass undeviated, the deviation produced by the 2 prisms should be equal
$({\mu }_1-1)A_1=({\mu }_2-1)A_2$
Substituting the respective values, we get,
$A_2=1.2$