Unpolarized light is passed through polarizer 1. The light then goes though polarizer 2 with its plane of polarization at 40.7° to that of polarizer 1. Polarizer 3 is placed after polarizer 2. Polarizer 3 has its plane of polarization at 54.8° to the plane of polarization of polarizer 2 and at 95.5° to that of polarizer 1. What fraction of the intensity of the original light gets though the last polarizer?

Respuesta :

Answer:

The fraction of the intensity of the original light that got through the last polarizer is  [tex]\frac{I_3}{I_o} = 0.0955[/tex]

Explanation:

   From the question we are told that  

       The angle between polarizer 2  and polarizer 1 is  [tex]\theta_1 = 40.7^o[/tex]

       The angle between polarizer 3 and polarizer 2 is  [tex]\theta_ 2 = 54.8^o[/tex]

        The angle between polarizer 3 and polarizer 1 is [tex]\theta _3 = 95.5^o[/tex]

   

The intensity of light emerging from the first polarizer can be obtained using the one half rule as follows

               [tex]I_1 = \frac{I_o}{2}[/tex]

Here [tex]I_1[/tex] is the intensity of light emerging from the polarizer 1

         [tex]I_o[/tex] is the intensity of the unpolarized light

The intensity [tex](I_2)[/tex]of light emerging from the second polarizer is obtained using the cosine-squared rule the intensity of light incidenting on the second polarizer is already polarized by the polarizer 1

    So the intensity is mathematically represented as

              [tex]I_2 = I_1 cos^2 \theta_1[/tex]

  substituting for [tex]I_1[/tex]

               [tex]I_2 = \frac{I_o}{2} cos^2 \theta_1[/tex]

Substituting values

                   [tex]I_2 = \frac{I_0}{2} cos^2 (40.7)[/tex]

The intensity [tex](I_3)[/tex]  emerging from polarizer 3 is obtained using the cosine-squared rule as follows

                  [tex]I_3 = I_2 cos^2 \theta_2[/tex]

substituting for [tex]I_2 \ and \ \theta_2[/tex]

                  [tex]I_3 = \frac{I_o}{2} cos^2 (40.7) \ cos^2 (54.8)[/tex]

                         [tex]I_3 = \frac{I_o}{2} \ 0.5748 * 0.3323[/tex]

                        [tex]I_3 =(0.0955) I_o[/tex]

                           [tex]\frac{I_3}{I_o} = 0.0955[/tex]