Question

Flint glass prism is joined by a crown glass prism to produce dispersion without deviation. The refractive indices of these for mean rays are 1.602 and 1.500 respectively. Angle of prism of flint prism is 10^o, then the angle of prism for crown prism will be

• A. ${12}^{\circ }{2.4}^{\prime }$
• B. ${12}^{\circ }{4}^{\prime }$
• C. ${1.24}^{\circ }$
• D. ${12}^{\circ }$

Answer 1

The correct option is A ${12}^{\circ }{2.4}^{\prime }$

For dispersion without deviation $\frac{A_C}{A_F}=\frac{({\mu }_F-1)}{({\mu }_C-1)}\Rightarrow \frac{A}{10}=\frac{(1.602-1)}{(1.500-1)}\Rightarrow A={12.04}^{\circ }={12}^{\circ }{2.4}^{\prime }$