Question

An unpolarised beam of intensity $I_{0}$ is incident on a pair of nicols making an angle of $60^{\circ}$ with each other. The intensity of light emerging from the pair is

• A. $I_0$
• B. $\frac{I_0}{2}$
• C. $\frac{I_0}{4}$
• D. $\frac{I_0}{8}$

Answer 1

Answer: (C)

$\frac{I_0}{4}$

Answer 2

According to Malus' law $I =I_{0} \cos ^{2} \theta$ $=I_{0}\left(\cos ^{2} 60^{\circ}\right)$ $=I_{0} \times\left(\frac{1}{2}\right)^{2}$ $=\frac{I_{0}}{4}$