Answer: the intensity of the light that passes through the set of polarizers is 0.7285 S₀
Step-by-step 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