'$n$' polarizing sheets are arranged such that each makes an angle $45^{\circ}$ with the preceeding sheet. An unpolarized light of intensity I is incident into this arrangement. The output intensity is found to be $I / 64$. The value of $n$ will be:
Solution
After passing through first sheet
<br/><br/>$I_1=\frac{I}{2}$
<br/><br/>After passing through second sheet
<br/><br/>$I_2=I_1 \cos ^2\left(45^{\circ}\right)=\frac{I}{4}$
<br/><br/>After passing through $n^{\text {th }}$ sheet
<br/><br/>$$
\begin{aligned}
& I_{\mathrm{n}}=\frac{I}{2^{\mathrm{n}}}=\frac{I}{64} \\\\
& n=6
\end{aligned}
$$
About this question
Subject: Physics · Chapter: Optics · Topic: Reflection and Mirrors
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