How is the refractive index of a medium related to the speed of light ? Obtain an expression for refractive index of a medium with respect to another in terms of speed of light in these two media ?

Explanation

`n = c/v`, where c is velocity of light in vacuum and v is velocity of light in the medium. If `v_(1)` is velocity of light in medium of refractive index `n_(1)` and `n_(2)` is velocity of light in another medium of refractive index `n_(2)`, then
`n_(1) = ( c)/(v_(1)` and `n_(2) = ( c)/(v_(2))`
`.^(1)n_(2) = (n_(2))/(n_(1)) = (c//v_(2))/(c//v_(1)) = (v_(1))/(v_(2))`.