JEE Advanced 2024 Paper 2, Physics Section 4 Q1: Young’s Double Slit Experiment

PARAGRAPH I

In a Young's double slit experiment, each of the two slits $A$ and $B$, as shown in the figure, are oscillating about their fixed center and with a mean separation of $0.8$ mm. The distance between the slits at time $t$ is given by $d=(0.8+0.04\sin \omega t)$ mm, where $\omega =0.08$ rad s${}^{-1}$. The distance of the screen from the slits is $1$ m and the wavelength of the light used to illuminate the slits is $6000$ Å. The interference pattern on the screen changes with time, while the central bright fringe (zeroth fringe) remains fixed at point $O$.

Q1. The $8^{th}$ bright fringe above the point $O$ oscillates with time between two extreme positions. The separation between these two extreme positions, in micrometer ($\mu$m), is ______.