Q 12-10-091JEE MainJEE Main 2023 (1 Feb, Shift 1)Medium
$n$ polarizing sheets are arranged such that each makes an angle $45^\circ$ with the preceding sheet. An unpolarized light of intensity $I$ is incident into this arrangement. The output intensity is found to be $\dfrac I{64}$. The value of $n$ will be
Answer: (B) 6
After the first sheet: $\dfrac I2$; each further sheet multiplies by $\cos^245^\circ=\dfrac12$:
$$\frac I2\left(\frac12\right)^{n-1}=\frac I{64}\ \Rightarrow\ n-1=5\ \Rightarrow\ n=6$$
Solution by Sreeraj P, M.Sc Physics