Question

Two polaroids are crossed. If now one of them is rotated through ${30}^0$ and unpolarised light of intensity $I_0$ is incident on the first polaroid,then the intensity of transmitted light will be

• A. $\frac{I_0}{4}$
• B. $\frac{3I_0}{4}$
• C. $\frac{3I_0}{8}$
• D. $\frac{I_0}{8}$

Answer 1

The correct option is D $\frac{I_0}{8}$

Intensity of transmit light transmitted from second Polaroid
$I_1=\frac{I_0}{2}$
Therefore,intensity of light transmitted from second polaroid

$I_2=I_{1}co{s}^2\theta$

$\frac{I_0}{2}co{s}^2({90}^0-{30}^0)$

$\frac{I_0}{2}co{s}^2{60}^0$

$\frac{I_0}{2}\times (\frac{1}{2}{)}^2=\frac{I_0}{8}$