Intensity of light through two polarizers and Malus's Law

[Linus Pauling]

1. A beam of unpolarized light with intensity I_0 falls first upon a polarizer with transmission axis theta1 then upon a second polarizer with transmission axis theta2, where theta2 - theta 1 = 90 degrees (in other words the two axes are perpendicular to one another). What is the intensity I_2 of the light beam emerging from the second polarizer?



2. Malus's Law



3. Would the answer be 0.25I₀, i.e. the intensity is cut in half each time, so the final intensity is 1/4 the initial intensity?

 

[Linus Pauling]

Actually, is it just 0?

 

[ehild]

Can light go through the crossed polarizers?

Half the intensity is transmitted if the incident beam is unpolarized, but after the first polarizer, it is polarized.


ehild