# Homework Help: Hi -- help please on a refraction problem

1. Dec 16, 2015

### Hello2016

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

I know that the depth is 30 cm , the apprared depth to the observer is 15 cm. But how am i gonna use snells law to get the refracted and incident angle when i have no idea what the index of refraction is for n2 liquid? ?

2. Relevant equations
N1sin1=n2sin2

3. The attempt at a solution
Im trying to use smells law to figure out both angles but im missing the index of refraction and i dont know how to compute it using the depth and length given View attachment 93432

Last edited by a moderator: Dec 16, 2015
2. Dec 16, 2015

### nrqed

You need to figure out the angles using geometry, from the figure drawn. Only after that do you use Snell's law to find the index of refraction.

3. Dec 16, 2015

### Hello2016

Oh so like tan sin and cos?

4. Dec 16, 2015

### nrqed

Yes, draw right angle triangles, use the apparent and real depths to get the sides of some triangles and then use trigonometry to find the angles.

5. Dec 16, 2015

### Hello2016

Hey im not sure how i should use x in the geometry