Unpolarized Light Intensity

1. Apr 12, 2009

hardwork

1. The problem statement, all variables and given/known data
Unpolarized light has intensity 15W/m^2 and is incident on a sheet of polarizing material whose transmission axis makes an angle of 25 degrees with the vertical. A second polarizer, whose transmission axis is horizontal, is located just past the first.

(a) What is the intensity of the light after it is transmitted through the first polarizer?
(b) What is the intensity of the light after it is transmitted through the second polarizer?

2. Relevant equations
I = (1/2)Io
I = Io(cos theta)^2

3. The attempt at a solution
a) I = (1/2)(15W/m^2) = 7.5W/m^2 -- haha sorry. I had it set up differently before, and put in the wrong answer.

b) How would I set this up? Would the angle be 90-25?

Last edited: Apr 12, 2009
2. Apr 12, 2009

Staff: Mentor

Check that arithmetic. :uhh:

Yes. So by what additional factor would the intensity be reduced?

3. Apr 12, 2009

hardwork

b) I = (7.5W/m^2)(cos 65)^2 = 1.3 W/m^2

Thank you for your help today!

4. Apr 12, 2009

Staff: Mentor

Looks good. (And you're welcome.)