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 has an intensity $I_0$. The intensity of light finally coming out is

Question

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° relative to that of A. The intensity of emergent light is:

Answer 1

Step 1: Numerical value
$\frac{I_0}{2}\times\frac14\times\frac34 = \frac{3I_0}{32}$.

Step 2: Matching
Only option (B) has the factor $\frac{I_0}{2}$ with angles $60^{\circ}$ and $30^{\circ}$ between successive axes.

Final Answer:
Option B. \[ \boxed{\text{(B)}\ \frac{I_0}{2}\cos^260^{\circ}\cos^230^{\circ}} \]

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 has an intensity \(I_0\). The intensity of light finally coming out is

Show Hint

The Correct Option is B

Solution and Explanation

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