# Refraction by a transparent spherical surface

1. Sep 20, 2008

### bcjochim07

1. The problem statement, all variables and given/known data
Parallel light rays enter a transparent sphere along a line passing through the center of the sphere. The rays come to a focus on the far surface of the sphere. What is the sphere's index of refraction?

2. Relevant equations

3. The attempt at a solution
so I used the equation that relates object distances and image distances for spherical surfaces: n1/s + n2/s' = (n2-n1)/R

I am calling the radius of the sphere R

(1.00)/s + n2/2R = (n2-1.00)/R and I think for this case s$$\rightarrow$$$$\infty$$
so n2/2R = (n2-1)/R
n2 = 2(n2-1)
n2 = 2n2 -2
-n2=-2
so n2= 2.00 Is this correct?

2. Sep 20, 2008

### Kurdt

Staff Emeritus
Looks fine to me.