Polarization and decreasing intensity of light to 10%

[aChordate]

Homework Statement

In order to decrease the intensity of a beam of unpolarized light to 10% of its original
intensity using two polarizers, what is the required value of θ, the angle between the
transmission axes of the two polarizers?

Homework Equations

tanθ_B=n₂/n₁

The Attempt at a Solution

tanθ_B=n₂/n₁

I'm not sure how to do this. I read the section on polarization and there are no examples in the book.

 

[Saitama]

Homework Statement

In order to decrease the intensity of a beam of unpolarized light to 10% of its original
intensity using two polarizers, what is the required value of θ, the angle between the
transmission axes of the two polarizers?

Homework Equations

tanθ_B=n₂/n₁

The Attempt at a Solution

tanθ_B=n₂/n₁

I'm not sure how to do this. I read the section on polarization and there are no examples in the book.

You seem to have mixed up Brewster's law with the Law of Malus. Check you textbook about the Law of Malus.

 

[aChordate]

So my equation would change to S=S_o=cos²θ

Would it be:

1/10*I=1/2*I*cos²θ ?


1/5=cos²θ

θ=63.4°

?

 

[Saitama]

So my equation would change to S=S_o=cos²θ

Would it be:

1/10*I=1/2*I*cos²θ ?


1/5=cos²θ

θ=63.4°

?

Looks good to me.