Question

17. Unpolarized light passes through a system of two polarizers. What would the angle between the polarizers have to be in order to have 15% of the original intensity of light pass through the system?

Answer 1

The amount of light passing through a system of two polarizers can be quantitatively described by applying Malu's cosine squared law.

I = I₀*$\cos$².$\theta$...........(1)

Where , I =intensity of light passing through the analyzer (total amount of light),

I_{0 = the intensity of light that is incident upon the polarizer}

  _{$\theta$= angle between the transmission axes of the polarizer and analyzer}

_{from question ,} 0.15 I₀ = I

_{put the value of equation ....(1)}

COS$\theta$= $\sqrt{}$ (I / I_{0)= $\large \sqrt{}$ 0.15=0.387}

COs
(0.387)=$\large \theta$

$\large \theta$=67.21 degree

$\large \therefore$ the angle between the polarizers is 67.21 degree