The Cauchy's dispersion formula is:

The deviations caused in red,yellow,and violet colors for a crown glass prism are $2.84^\circ$,$3.28^\circ$,and $3.72^\circ$ respectively. The dispersive power of the prism material is:

Explain the refractive index for light of different colours.

Compare the dispersive powers of two prisms if one of them deviates the blue and red rays through $10^{\circ}$ and $6^{\circ}$ respectively,and the second prism through $8^{\circ}$ and $4.5^{\circ}$.

$A$ parallel beam of white light falls on a convex lens. Images of blue,yellow,and red light are formed on the other side of the lens at distances of $0.20 \ m$,$0.205 \ m$,and $0.214 \ m$ respectively. The dispersive power of the material of the lens will be:

The splitting of white light into several colours on passing through a glass prism is due to