Unpolarized light of intensity I passes through an ideal polarizer A. Another identical polarizer B is placed behind A. The intensity of light beyond B is found to be \(I/2\). Now another identical polarizer C is placed between A and B. The intensity beyond B is now found to be \(I/8\). The angle between polarizer A and C is :
Show Hint
- \(60^\circ\)
- \(30^\circ\)
- \(45^\circ\)
- \(0^\circ\)
The Correct Option is C
Solution and Explanation
With C at angle \(\theta\) to A, the angle between C and B is also \(\theta\).
By Malus's law: \(I_B=\frac I2\cos^2\theta\cdot\cos^2\theta=\frac I2\cos^4\theta\).
Given \(I_B=\frac I8\): \(\cos^4\theta=\frac14 \Rightarrow \cos^2\theta=\frac12 \Rightarrow \theta=45^\circ\).
Answer: (3) \(45^\circ\)
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