Question

Light that is polarized along the vertical direction is incident on a sheet of polarizing material. Only 94% of the intensity of the light passes through the sheet and strikes a second sheet of polarizing material. No light passes through the second sheet. What angle does the transmission axis of the second sheet make with the vertical?

Answer 1

If no light gets through the second material, it must be passing only light polarized in the horizontal direction (perpendicular to the "transmission axis") of the first sheet.

Answer 2

We can use Malus law to solve this problem, equaiton 24.7:



S=Socos2Θ



S=amount of light leaving

So = amount of light entering



We know that S/So = 94%, or 0.94



Now, to solve for Θ from Malus law

S/So =cos2 Θ



Θ=cos-1 sqrt (S/So)

Θ= cos-1 sqrt (0.94)



Θ= 14.18



We subtract this from 90 due to respct to the vertical



so 90-14.18= 75.82 degrees

Answer 3

The solution is almost correct, except that for the final answer it would be 90 + 14.18 = 104.18 degrees because the first sheet is already rotated 14.18 degrees from the vertical.

Answer 4

My apologies: the range for Θ is between 0 and 90 degrees, so the original answer of 75.82 degrees is correct.

Answer 5

No, the correct answer is 90 + 14.18 = 104.18

Answer 6

Both are correct. One (~75) rotates the opposite direction of the original rotation and one continues in the same direction (~104). The question asks the angle to the vertical.