What prevents the formation of an interference pattern when two independent light sources are used?
**Coherence** requires constant phase difference, two independent sources not coherent because phase random, prevents interference pattern, laser coherent, visibility of fringes determined by coherence, intensity and phase difference, coherent sources produce stable interference, incoherent intensity adds I = I₁+I₂ no interference, interference pattern distinguishes from diffraction. Independent sources lack a fixed phase relationship (incoherence), causing rapid phase fluctuations that average out interference effects. Using Δ = d sinθ, y = n λ D/d, a sinθ = n λ, I = I₀ cos²θ, n = c/v, sinC =
Ref: NCERT > Physics Book > Wave Optics > Interference - Double-Slit and Coherence