# Homework Help: Angle between polarizer and analyzer

1. Nov 17, 2013

### bobsmithe

1. The problem statement, all variables and given/known data
Consider a polarizer-analyzer arrangement, as shown (here's a link http://i.imgur.com/APZRJ6J.png )

At what angle is the axis of the analyzer to the axis of the polarizer if, after passing through both sheets, the beam intensity is reduced by 67.6 percent?

2. Relevant equations
I=(1/2)I_o
I=I_o*cos^2(∅)

3. The attempt at a solution
Since the beam intensity is reduced by 67.7%, I knew I/I_o was .676, so I tried doing ∅=cos($\sqrt{.676}$) but it wasn't right. I'm not sure what I did wrong and whether I'm supposed to use the first equation in this type of problem or not.

2. Nov 17, 2013

### BOYLANATOR

It wasn't reduced to 67.6 percent. It was reduced by 67.6 percent

3. Nov 17, 2013

### bobsmithe

so that would mean that .324I=I_o*cos^2(∅)?

Last edited: Nov 18, 2013
4. Nov 18, 2013

### bobsmithe

ok I got it. Thanks for pointing out my mistake