Refractive Index Calculation for Light Passing from Substance X to Substance Y

[disfused_3289]

Homework Statement

For substance X, the refractive index is nx. For another substance Y the refractive index ny. Show that the refractive index for light passing from x to y is nx/ ny.


2. The attempt at a solution

I'm finding it difficult to devise a solution, but I think the answer has a relation to the ratio of velocites to and from x and y.

 

[Shooting Star]

So just write down that formula first and let's see where it goes.

 

[disfused_3289]

refractive index

ny= vx/ vy
nx= vy/vx

ny/nx= 1 ?

 

[malawi_glenn]

The refractive index is veolcity in a perticular medium (i) compared to the veolcity in vacuum

$$n_i = c/v_i$$

c is velocity in vacuum

 

[Shooting Star]

ny= vx/ vy
nx= vy/vx

ny/nx= 1 ?

You know it's wrong. Use the correct formula as given.