Question

Find the final intensity of light $(I^{\prime \prime })$, if the angle between the axes of two polaroids is $60^{\circ }$.

• A. $\frac{3I_0}{2}$
• B. $\frac{I_0}{2}$
• C. $\frac{I_0}{4}$
• D. $\frac{I_0}{8}$

Answer 1

Answer: (D)

From the first polaroid
$I^{\prime }=\frac{I_0}{2}$
From second polaroid
$I"=I^{\prime }co{s}^2\theta =\frac{I_0}{2}co{s}^2\left(60^{\circ }\right)$
$=\frac{I_0}{2}\times {\left(\frac{1}{2}\right)}^{{}^2}=\frac{I_0}{8}$