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

The refractive index of flint glass for blue light is $1.6333$ and for red light is $1.6161$. Calculate the dispersive power of the prism,assuming the mean refractive index is approximately the average of the two given values.

Dispersive power depends on the following:

Explain dispersive and non-dispersive medium.

The angle of a prism is $10^o$. The refractive indices for red and violet colours are $1.51$ and $1.52$ respectively. Find the dispersive power.

For a medium,the refractive indices for violet,red,and yellow light are $1.62$,$1.52$,and $1.55$ respectively. Calculate the dispersive power of the medium.