Question

If the angle between the pass axis of the polarizer and the analyzer is 45⁰, the ratio of the intensities of original light and the transmitted light after passing through the analyzer is:

• A. $\frac{I}{2}$
• B. $\frac{I}{3}$
• C. I
• D. $\frac{I}{4}$

Answer 1

Answer: (D)

$\frac{I}{4}$

Answer 2

The intensity of the light after passing through the polariser

$I = I_{0}\cos^{2}\varphi = I_{0}\cos^{2}45º$

$= I_{0}\left( \frac{1}{\sqrt{2}} \right)^{2} = \frac{I}{2} \times \frac{1}{2} = \frac{I}{4}$ $\left( \because I_{0} = \frac{1}{2} \right)$