# Polarizing filters

1. Jul 9, 2008

### solars

Which combo of polarizing filters allows most light to pass through? Each orientation is given with respect to vertical
unit of following values given are angles:
1. 0, 45, 90
2. 30, 60, 90
3. 180, 0, 180
4. 90, 135, 180
5. 10,20,100

I tried by using the formulas:
I1=0.5Inought
I2=I1*cos^2(theta)
I3=I2*cos^2(theta)

so bascially I multiplied cos^2(theta1) *cos^2(theta2) *cos^2(theta3) and chose the biggest value. Am I doing this right? Can I just plug in the angles given directly or do I have to subtract something from them?

2. Jul 9, 2008

### tiny-tim

Hi solars!

Isn't it the difference between the angles that matters?

3. Jul 9, 2008

### DaveC426913

I've done this experiment for real (when I worked in a camera store).

It's really cool.

Put 2 filters together at 90 degrees to each other. Completely opaque.
Slip a 3rd one between them at a 45 degree angle. Suddenly, you can see through all three!

Manager says "How does that help us sell more accessories?"

4. Jul 9, 2008

### solars

oh so it should be 3 then? thanks for the help guys =)