$P_1$ and $P_2$are two polaroids

The intensity of the unpolarised is Io and intensity of the transmitted height is $\frac{3I_0}{8}$. The angle between axis of $P_1$ and $P_2$ is:

30°

The correct answer is Option (1) → 30°

According to Malus' Law,

$I=I_0\cos^2θ$

$⇒\frac{3I_0}{8}=I_0\cos^2θ$

$⇒\cos^2θ=\frac{3}{4}$

$⇒\cos θ=\sqrt{\frac{3}{4}}$

$∴θ=\cos^{-1}\frac{\sqrt{3}}{2}=30°$