Directly proportional to pressure
<span>θ is the angle whose tangent is 3/0.4 = arctan (7.5) = 82.4°
(That's the angle above the horizontal. If that doesn't match
the </span><span>θ in your diagram, too bad ! For some strange reason,
I wasn't able to see your diagram.)
</span>
Polarization is the action of restricting the vibrations of a transverse wave, especially light, wholly or partially to one direction .