In Young's double slit experiment, the distance between the slits is 2 mm and the slits are 1 m away, from the screen. Two interference patterns can be obtained on the screen due to light of wavelength ' λ₁ ' and ' λ₂ ' respectively. The separation on the screen between the 3 rd order bright fringes on the two interference patterns is ( λ₂ = 1.5λ₁) (a) (0.75 × 10⁺³)λ₁ (b) (1.75 × 10⁺³)λ₁ (c) (2.00 × 10⁺³)λ₁ (d) (2.25 × 10⁺³)λ₁

Answer: (a). Δ y = (n(λ₂ - λ₁)D)/(d) with λ₂ - λ₁ = 0.5λ₁. Δ y = 3 × 0.5λ₁ × 12×10⁻³ = 0.75×10³λ₁ So the answer is (a) (0.75 × 10³)λ₁.

In Young's double slit experiment, the distance between the slits is… | MHT CET 2025 (26 Apr, Shift 1)

Q26MHT CET 2025 · 26 APR · SHIFT 1Medium

YDSE: Film, Medium & Two Wavelengths

In Young's double slit experiment, the distance between the slits is 2 mm and the slits are 1 m away, from the screen. Two interference patterns can be obtained on the screen due to light of wavelength ' $\lambda_1$ ' and ' $\lambda_2$ ' respectively. The separation on the screen between the $3$ rd order bright fringes on the two interference patterns is ( $\lambda_2 = 1.5\lambda_1$ )

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Answer: (a)

$\Delta y = \dfrac{n(\lambda_2 - \lambda_1)D}{d}$ with $\lambda_2 - \lambda_1 = 0.5\lambda_1$ .
$\Delta y = \dfrac{3 \times 0.5\lambda_1 \times 1}{2\times10^{-3}} = 0.75\times10^{3}\lambda_1$
So the answer is (a) $(0.75 \times 10^{3})\lambda_1$ .

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