What is the distance of the first dark fringe from the central maximum in a double-slit experiment if \( \lambda = 540 \
**Interference** occurs when two coherent waves superpose, path difference Δ = d sinθ, bright fringe when Δ = n λ, n integer, seventh bright Δ=7λ, dark fringe Δ = (2n-1)λ/2, second dark Δ=3λ/2, third dark 5λ/2, sixth dark 11λ/2, distance of bright fringe from central y = n λ D/d, D screen distance, d slit separation, for λ=650 nm d=0.5 mm D=1.0 m fifth dark? Actually dark y=(2n-1)λ D/(2d). Dark fringe position x_n = ((n + (1/2)) λ D/d) . For the first dark fringe, n = 0 . λ = 5.4 × 10⁻⁷ m , d = 2.0 × 10⁻⁴ m , D =
Ref: NCERT > Physics Book > Wave Optics > Interference - Double-Slit and Coherence