JEE Main 2025 — 24 January, Evening Shift — Question 63

In a Young's double slit experiment, three polarizers are kept as shown in the figure. The transmission axes of $P_{1}$ and $P_{2}$ are orthogonal to each other. The polarizer $P_{3}$ covers both the slits with its transmission axis at $45^{\circ}$ to those of $\mathrm{P}_{1}$ and $P_{2}$. An unpolarized light of wavelength $\lambda$ and intensity $\mathrm{I}_{0}$ is incident on $\mathrm{P}_{1}$ and $\mathrm{P}_{2}$. The intensity at a point after $P_{3}$ where the path difference between the light waves from $\mathrm{s}_{1}$ and $\mathrm{s}_{2}$ is $\frac{\lambda}{3}$, is