Q 12-10-023NEETJEE MainEasy
Unpolarised light of intensity $I_0$ passes through two polaroids whose axes are at $60°$. The intensity of the emergent light is
Answer: (D) $\dfrac{I_0}{8}$
Concept. The first polaroid passes half of unpolarised light; Malus's law at the second.
Step 1. After the first. $\dfrac{I_0}{2}$.
Step 2. After the second. $\dfrac{I_0}{2}\cos^260° = \dfrac{I_0}{8}$.
Answer. $\dfrac{I_0}{8}$ (Option D).
Solution by Sreeraj P, M.Sc Physics