The focal length of a lens is $20 \ cm$ and its dispersive power is $0.08$. What is its longitudinal chromatic aberration in $cm$?

In the phenomenon of dispersion without deviation,which of the following statements is true?

Dispersion of light is due to

Dispersive power depends on the following:

If the refractive indices of a prism for red,yellow,and violet colours are $1.61$,$1.63$,and $1.65$ respectively,then the dispersive power of the prism will be:

The Cauchy's dispersion formula is: