What was the initial polarization direction of the incident light?

[xQuin]

Homework Statement

Two polarizers are oriented at 40deg to each other and plane-polarized light is incident on them. If only 15% of the light gets through both of them, what twas the initial polarization directon of the incident light?

Homework Equations

The Attempt at a Solution

I think it ha something to do with Malus's Law but I'm not sure exactly how

 

[tiny-tim]

welcome to pf!

hi xQuin! welcome to pf!

yes, assume that the angle of polarization to the first polarizer is θ …

how much goes through the first polarizer, and how much of that goes through the second?

show us what you get ​

 

[xQuin]

Thanks tim, I applied the law twice and managed to get an answer of 59.6deg =D

 

[tiny-tim]

looks good!