# Refractive index question

1. Jan 12, 2008

### disfused_3289

1. The problem statement, all variables and given/known data

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.

2. Jan 12, 2008

### Shooting Star

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

3. Jan 12, 2008

### disfused_3289

refractive index

ny= vx/ vy
nx= vy/vx

ny/nx= 1 ?

4. Jan 12, 2008

### 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

5. Jan 12, 2008

### Shooting Star

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