Q 12-10-093JEE MainJEE Main 2022 (24 Jun, Shift 1)Medium
Sodium light of wavelengths $650\ \text{nm}$ and $655\ \text{nm}$ is used to study diffraction at a single slit of aperture $0.5\ \text{mm}$. The distance between the slit and the screen is $2.0\ \text{m}$. The separation between the positions of the first maxima of diffraction pattern obtained in the two cases is ______ $\times10^{-5}\ \text{m}$.
Numerical value type. Enter your answer.
Answer: 3
The first secondary maximum is at $y \approx \dfrac{3\lambda D}{2a}$, so
$$\Delta y = \frac{3D\,\Delta\lambda}{2a} = \frac{3\times2\times5\times10^{-9}}{2\times0.5\times10^{-3}} = 3\times10^{-5}\ \text{m}$$
Solution by Sreeraj P, M.Sc Physics