Wave Optics Question 11
Question 11 - 01 February - Shift 1
’ $n$ ’ polarizing sheets are arranged such that each makes an angle $45^{\circ}$ with the proceeding sheet. An unpolarized light of intensity $I$ is incident into this arrangement. The output intensity is found to be $\frac{I}{64}$. The value of $n$ will be:
(1) 3
(2) 6
(3) 5
(4) 4
Show Answer
Answer: (2)
Solution:
Formula: YDSE
After passing through first sheet
$ I_1=\frac{I}{2} $
After passing through second sheet
$ I_2=I_1 \cos ^{2}(45^{\circ})=\frac{I}{4} $
After passing through $n^{\text{th }}$ sheet
$ \begin{aligned} & I_n=\frac{I}{2^{n}}=\frac{I}{64} \\ & n=6 \end{aligned} $
