# Radius of a circle from refracted light in water

1. Apr 8, 2008

### snoweangel27

[SOLVED] radius of a circle from refracted light in water

1. The problem statement, all variables and given/known data
A swimmer at the bottom of a pool 4 m deep looks up and sees a circle of light. If the index of refraction of the water in the pool is 1.33, find the radius of the circle.

2. Relevant equations
$$\theta$$ (c) = Arcsin(n$$_{2}$$/n$$_{1}$$)
n(1)*sin$$\theta$$(1) = n(2) * sin$$\theta$$(2)

3. The attempt at a solution
I used to first equation to find the angle of incidence, then used snell's law to calculate the angle of refraction. After which I am unsure of the correct way to proceed. I tried setting tan$$\theta$$ = 4/x, where I was using x as the radius, but I am pretty sure that it is not correct.