Respuesta :
To determine the intensity, the key idea is to work through the system filter-by-filter and applying either the one-half rule for unpolarized light or the cosine-squared rule for an already polarized light.
When the light reach the first filter, it is unpolarized, so the intensity is :
      I1 = 1/2 I0           (One-half rule)
Because the light reaching the second filter is polarized, given 43° angle difference, the intensity is :Â
      I2 = I0 cos^2 (angle difference)
        = I0 cos^2 43°
        = 0.535 I0
Lastly, when the light reached the third filter, it is polarized and has angle diference equals to the angle between the second and last filter 47°. Using the same rule, we get :
      I3 = I2 cos^2 47°
        = (0.535 I0) cos^2 47°
        = (0.535 I0) (0.465)
        = 0.249 I0
So, the intensity which emerges is 0.249 I0.
When the light reach the first filter, it is unpolarized, so the intensity is :
      I1 = 1/2 I0           (One-half rule)
Because the light reaching the second filter is polarized, given 43° angle difference, the intensity is :Â
      I2 = I0 cos^2 (angle difference)
        = I0 cos^2 43°
        = 0.535 I0
Lastly, when the light reached the third filter, it is polarized and has angle diference equals to the angle between the second and last filter 47°. Using the same rule, we get :
      I3 = I2 cos^2 47°
        = (0.535 I0) cos^2 47°
        = (0.535 I0) (0.465)
        = 0.249 I0
So, the intensity which emerges is 0.249 I0.
