Physics - Wave Optics Question with Solution | TestHub

Intensity of unpolarized light is $I_0$.

Intensity of light after passing through the first polarizer $P_1$ is:

$I_1=\frac{I_0}{2}$

The polarization axis of $P_2$ makes an angle of $60^{\circ }$ with $P_1$. According to Malus's law, the intensity after passing through $P_2$ is:

$I_2=I_1{\cos }^2(60^{\circ })=\frac{I_0}{2}\times {\left(\frac{1}{2}\right)}^2=\frac{I_0}{8}$

The polarization axis of $P_3$ makes an angle of $45^{\circ }$ with $P_2$. The intensity after passing through $P_3$ is:

$I_3=I_2{\cos }^2(45^{\circ })=\frac{I_0}{8}\times {\left(\frac{1}{\sqrt{2}}\right)}^2=\frac{I_0}{16}$

Given $I_0=x{I}_3$, substituting the value of $I_3$ gives:

$I_0=x\left(\frac{I_0}{16}\right)$

$x=16$

Answer: $16$