Q137 / 200 · NEET 2024 (Re-NEET) · Physics

A beam of unpolarized light of intensity $I_0$ is passed through a polaroid $A$, then through another polaroid $B$, oriented at $60^{\circ}$ and finally through another polaroid $C$, oriented at $45^{\circ}$ relative to $B$ as shown. The intensity of emergent light is: Figure

  • Correct answer
    A
    $\frac{I_0}{16}$
  • B
    $\frac{I_0}{4}$
  • C
    $\frac{I_0}{2}$
  • D
    $\frac{I_0}{32}$

Solution

$I_1=\frac{I_0}{2}$ $I_B=\left(I_1\right) \cos ^2 60^{\circ}$ $=\frac{I_0}{2}\left(\frac{1}{2}\right)^2=\frac{I_0}{8}$ $I_C=I_B \cos ^2 45^{\circ}$ $=\frac{I_0}{8} \times\left(\frac{1}{\sqrt{2}}\right)^2=\frac{I_0}{16}$

Hence, the correct answer is option: 'A'.

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