Is the speed of light in glass independent of the colour of light? If not, which of the two colours red and violet travels slower in a glass prism?

Explanation

We are given:
Refractive index of glass (n) = 1.5
Speed of light of glass (c)=`3xx10^(8)"m/s"`
We are to calculate, (a) Speed of light in glass
(b) To determine whether speed of light is glass depends on colour or not.
Usinf relation: (a) `v=c/(n)=(3xx10^(8))/(1.5)=2xx10^(8)"m/s"` (b) Using Cauchy.s formula
`n=A+B/(lamda^(2))+...rArrc/(v)=A+B/(lamda^(2))+...(i)`
It is clear from equation (i) that speed of light depends upon colour of light.
violet colour travels slower in the glass prism, because of its smaller wavelength.