# Homework Help: Snell's Law Problem

1. Nov 8, 2008

### haxxorboi

1. The problem statement, all variables and given/known data
A fish is 30 cm below the surface of a lake.
If he looks up he can see the entire sky compressed in a cone of angle θ, because of refraction of light at the water surface. (θ is the angle between the cone axis and the cone surface.) Determine θ.

2. Relevant equations
n1*sin(theta 1)=n2*sin(theta 2)
n1=1
n2=1.33
theta 1=90
theta 2=?

3. The attempt at a solution
sin(90)/1.33=sin(theta 2)
sin-1(0.672177943)=42.24 degrees

This doesn't seem to be the answer though...

Any help?

2. Nov 8, 2008

### jcvince17

i do it i get:

1sin90 = 1.33sin(theta 2)
1 = 1.33sin(theta 2)
1/1.33 = sin(theta 2)
.7518796992 = sin(theta 2)
sin-1(.7518796992) = 48.75 degrees

3. Nov 8, 2008

### haxxorboi

Man, what the heck was I doing? I did it again and I got the same answer as you, which is the correct answer...

I swear I just do things wrong 10 times in a row for no reason...

Thanks for the help!

4. Nov 8, 2008

### jcvince17

no problem...i am the same way sometimes.

sometimes you just need a clear head to straighten it out.