Two wavelengths of sodium light 590 nm and 596 nm are used one after another to study diffraction due to single slit of aperture 2 × 10⁻⁶ m. The distance between the slit and the screen is 1.5 m. The separation between the positions of first maximum of the diffraction pattern obtained in the two cases is (a) 5.5 mm (b) 5.75 mm (c) 6.25 mm (d) 6.75 mm

Answer: (d). First maximum (first secondary maximum): y = (3λ D)/(2a), so Δ y = (3D Δλ)/(2a) Δ y = 3 × 1.5 × 6 × 10⁻⁹2 × 2 × 10⁻⁶ = 6.75 × 10⁻³ m So the answer is (d) 6.75 mm.

Two wavelengths of sodium light 590 nm and 596 nm are used one after… | MHT CET 2023 (14 May, Shift 2)

Q50MHT CET 2023 · 14 MAY · SHIFT 2Medium

Diffraction at a Single Slit

Two wavelengths of sodium light $590\text{ nm}$ and $596\text{ nm}$ are used one after another to study diffraction due to single slit of aperture $2 \times 10^{-6}\text{ m}$ . The distance between the slit and the screen is $1.5\text{ m}$ . The separation between the positions of first maximum of the diffraction pattern obtained in the two cases is

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Answer: (d)

First maximum (first secondary maximum): $y = \dfrac{3\lambda D}{2a}$ , so $\Delta y = \dfrac{3D\,\Delta\lambda}{2a}$
$\Delta y = \dfrac{3 \times 1.5 \times 6 \times 10^{-9}}{2 \times 2 \times 10^{-6}} = 6.75 \times 10^{-3}$ m
So the answer is (d) $6.75$ mm.

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Diffraction at a Single Slit question from MHT CET 2023 (14 May, Shift 2)

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