Optics Ques 130

  1. A beam of unpolarised light of intensity $I _0$ is passed through a polaroid $A$ and then through another polaroid $B$ which is oriented so that its principal plane makes an angle of $45^{\circ}$ relative to that of $A$. The intensity of the emergent light is

(a) $I _0$

(b) $I _0 / 2$

(c) $I _0 / 4$

(d) $I _0 / 8$

(2013 Main)

Show Answer

Answer:

Correct Answer: 130.(c)

Solution:

Formula:

Law of Malus

  1. Relation between intensities is

$ I _R=(\frac{I _0}{2} )\cos ^{2}\left(45^{\circ}\right)=\frac{I _0}{2} \times \frac{1}{2}=\frac{I _0}{4} $



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