The angle between the polarizer transmission axis and the plane of polarization of the incoming light is 30 +/- 2 deg. If the incident light intensity Io is 100 W/cm2 what would be the intensity I after the light is transmitted through the polarizer? What would be the percent error in intensity?

Answer 1

I = 100 cos30 = 86.6

Max = 100 cos28 = 88.3
Min = 100 cos32 = 84.8

Percent error: +/- 2%

This assumes a lossless polarizer (when aligned in the proper plane), such as a Wollaston or Nicol prism type. Polaroid sheet film has large losses, even in the plane of polarization.

It also assumes that the incoming radiation is perfectly plane-polarized.