contestada

Polarizers 1 and 3 have their axes of polarization indicated by the black solid lines, perpendicular to each other. Polarizer 2 has an axis of polarization that has an angle of θ = 50.9° with respect to the polarization axis of polarizer 1. What percentage of the initial (unpolarized) light intensity passes through?

Respuesta :

Answer:

percentage of unpolarized light intensity,

[tex]\frac{I"'}{I} = 8.52%[/tex]

Given:

Polarization angle for the 2nd polarizer, [tex]\theta = 50.9^{\circ}[/tex]

Solution:

If I be the intensity of unpolarized light, then the intensity of light passing through the first polarizer, I':

[tex]I' = \frac{I}{2}[/tex]

Now, the intensity of light through polarizer 2, I":

[tex]I" = I'cos^{2}\theta = \frac{I}{2}cos^{2}\theta[/tex]

Also Polarizer 1 and 3 are perpendicular to each other:

Therefore, [tex]\theta' = 90^{\circ} - 50.9^{\circ} = 49.1^{\circ}[/tex]

Intensity of light passing through polarizer 3:

[tex]I"' = I" cos^{2}\theta' =  \frac{I}{2}cos^{2}\theta  cos^{2}\theta' [/tex]

[tex]I"' = \frac{I}{2}cos^{2}50.9^{\circ}\times cos^{2}49.1^{\circ}[/tex]

I"' = 0.0852 I

Now, percentage of unpolarized light intensity:

[tex]\frac{I"'}{I}\times 100 = 0.0852\times 100 = 8.52%[/tex]