Light of intensity So and polarized horizontally passes through three polarizes. The first and third are horizontal, but the second is oriented 0.3927 rad to the horizontal. In terms of So , what is the intensity of the light that passes through the set of polarizers

the intensity of the light that passes through the set of polarizers is  0.7285 S₀

Explanation:

based on the data in the question;

As the first polarizer lets all the light through because its plane of polarization is not different from light.

The second polarizer has 2 effects;

firstly, it reduces the intensity by a factor cos²0.3927^c; if you switch the calculator to radians mode, this will give you 0.85355

Secondly; it changes the plane of polarization of the light to be the same as the polarizer; therefore the light now has a plane of polarization of 0.3927 rad to the horizontal.

Hence;

after the second effect, the light enters the third polarizer at 0.3927 rad to the plane of polarization of third polarizer. So the intensity is again reduced by a factor 0.85355.

Therefore

the Overall reduction is by a factor of 0.85355 × 0.85355 S₀

= 0.7285 S₀

Therefore the intensity of the light that passes through the set of polarizers is  0.7285 S₀

ill do it for 100, also this isnt 80 its 40

do you have a formula possibly