# At what angle does the light leave the glass?

1. Mar 29, 2009

### phys62

1. The problem statement, all variables and given/known data
The drawing shows a rectangular block of glass (n = 1.52) surrounded by a liquid with n = 1.60. A ray of light is incident on the glass at point A with a 30.0° angle of incidence. At what angle does the ray leave the glass at point B?

http://edugen.wiley.com/edugen/courses/crs1507/art/qb/qu/c26/ch26p_18.gif

2. Relevant equations
n1sintheta1 = n2sintheta2

3. The attempt at a solution
(1.52)sin(30) = (1.6)sintheta2
theta2 = 28.359

I have no idea what I did wrong.. should the angle be negative??

2. Mar 29, 2009

### rl.bhat

theta2 = 28.359
This is the angle of refraction at point A. From that find the angle of incidence on the surface containing point B.

3. Mar 29, 2009

### phys62

Ohh, is this right then..?

sintheta2 = (1.6) sin30/1
theta2 = 53.13

4. Mar 29, 2009

### phys62

Nevermind, I got it :] 53.13 degrees is the answer. Thanks!

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