If the refractive indices of crown glass for red, yellow and violet colours are respectively ${\mu }_r,{\mu }_y,{\mu }_v$, then the dispersive power of this glass would be

Q. Three thin prisms are combined as shown in figure. The refractive indices of the crown glass for red, yellow and violet rays are μ_r, μ_y and μ_v respectively and those for the flint glass are μ'_r, μ'_y and μ'_v respectively. Find the ratio A'/A for which (a) there is no net angular dispersion, and (b) there is no net deviation in the yellow ray.
Figure

Q. In a prism, the refractive indices of different colours are
${\mu }_V=$ 1.6;
${\mu }_R=$ 1.52;
${\mu }_Y=$ 1.56.
The dispersive power of the prism is :

Q. Three thin prisms are combined as shown in figure. The refractive indices of the crown glass for red, yellow and violet rays are ${\mu }_r,$ ${\mu }_y$ and ${\mu }_v$ respectively and those for the flint glass are ${\mu }_r^{{}^{\prime }}$, ${\mu }_y^{{}^{\prime }}$ and ${\mu }_v^{{}^{\prime }}$ respectively. Find the $\frac{A^{\prime }}{A}$ for which, there is no net angular dispersion.

Q. Three thin prisms are combined as shown in figure. The refractive indices of the crown glass for red, yellow and violet lights are ${\mu }_r,{\mu }_y$ and ${\mu }_v$ respectively and those for the flint glass are ${\mu }_r^{{}^{\prime }},{\mu }_y^{{}^{\prime }}$ and ${\mu }_v^{{}^{\prime }}$ respectively. Find the $\frac{A^{{}^{\prime }}}{A}$ for which, there is no net angular dispersion.

Q. Three thin prisms are combined as shown in figure. The refractive indices of the crown glass for red, yellow and violet rays are ${\mu }_r,{\mu }_y$ and ${\mu }_v$ respectively and those for the flint glass are ${\mu }_r^{{}^{\prime }},{\mu }_y^{{}^{\prime }}$ and ${\mu }_v^{{}^{\prime }}$ respectively. Find $\frac{A^{{}^{\prime }}}{A}$ for which, there is no net deviation in the yellow light.