In Young’s double slit experiment, two slits S₁ and S₂ are d distance apart and the separation from slits to screen is D. If two transparent slabs of equal thickness 0.1 mm but refractive indices 1.51 and 1.55 are introduced in the paths from S₁ and S₂ respectively, with λ = 4000 Å, the central bright fringe spot will shift by ______ number of fringes. Image
Physics · Circular Motion
JEE Mains 30 January 2023 Shift 1 Morning Shift

Question

In Young’s double slit experiment, two slits S₁ and S₂ are d distance apart and the separation from slits to screen is D. If two transparent slabs of equal thickness 0.1 mm but refractive indices 1.51 and 1.55 are introduced in the paths from S₁ and S₂ respectively, with λ = 4000 Å, the central bright fringe spot will shift by ______ number of fringes. Image

Physics · Circular Motion

G1 Physics · Accepted Answer

Additional path difference = (1.55−1.51)(0.1 mm) = 0.04×10⁻⁴ m = 4×10⁻⁶ m. Number of fringe shifts = Δ/λ = (4×10⁻⁶)/(4×10⁻⁷) = 10.