(a) The refractive index of glass is 1.5. What is the speed of light in glass? `("Speed of light in vacuum is "3.0 xx 10^(8) m s^(-1))`
(b) 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

Refractive index of given transparent medium,
`n=(c)/(v)=("Speed of light in vacuum")/("Speed of light in given medium")`
`:.v=(c)/(n)=(3xx10^(8))/(1.5)=2xx10^(8)(m)/(s)`