Assertion `:` Dispersion of light occurs because velocity of light in a material depends upon its colour.
Reason `:` The dispersive power depends only upon the material of the prism, not upon the refracting angle of the prism

Options

A. If both the assertion and reason are true and reason explains the assertion.
B. If both the assertion and reason are true but reason does not explain the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Answer

B

Explanation

The velocity of light in a material medium depends upon its colour (wavelength ) . If a ray of white light incident on a prism, then on emerging, the different colours are deviated through differrent angles.
Also dispersive power `omega=((mu_(V)-mu_(R)))/((mu_(Y)-1))`