Question

A beam of unpolarized light of intensity I0 is passed through a polaroid A, then through another polaroid B, oriented at 60º and finally through another polaroid C, oriented at 45º relative to B as shown. The intensity of emergent light is:

• A. \(\frac{I_0}{16} \)
• B. \(\frac{I_0}{4} \)
• C. \(\frac{I_0}{2} \)
• D. \(\frac{I_0}{32} \)

Answer 1

The Correct Option is A

After the first polarizer: \(I_1 = \frac{I_0}{2}\)

After the second polarizer: \(I_2 = I_1 \cos^2 60^\circ = \frac{I_0}{2} \times \frac{1}{4} = \frac{I_0}{8}\)

After the third polarizer: \(I_3 = I_2 \cos^2 45^\circ = \frac{I_0}{8} \times \frac{1}{2} = \frac{I_0}{16}\)