Wave Optics Question 4
Question 4 - 29 January - Shift 1
As shown in figures, three identical polaroids $P_1$, $P_2$ and $P_3$ are placed one after another. The pass axis of $P_2$ and $P_3$ are inclined at angle of $60^{\circ}$ and $90^{\circ}$ with respect to axis of $P_1$. The source $S$ has an intensity of $256 \frac{W}{m^{2}}$. The intensity of light at point $O$ is $—–\frac{W}{m^{2}}$.
$P_1$
$P_2$
Show Answer
Answer: (24)
Solution:
Formula: YDSE
By first polaroid P1 intensity will be halved then
P2 and P3 will make intensity $\cos ^{2}(60^{\circ})$ and
$\cos ^{2}(30^{\circ})$ times respectively.
Intensity out $=\frac{256}{2} \times \frac{1}{4} \times(\frac{\sqrt{3}}{2})^{2}=\frac{256 \times 3}{2 \times 4 \times 4}=\mathbf{2 4}$
