Practice question

Given: In a double-slit experiment, if lambda = 450 nm, d = 0.15 mm, and D = 1.5 m, what is the fringe width? These values define the system as per NCERT data. Formula: Fringe width β = lambda D/d. This is standard NCERT relation. Substitution & Calculation: lambda = 4.5 × 10⁻⁷m, d = 1.5 × 10⁻⁴m, D = 1.5 m . β = frac4.5 × 10⁻⁷ × 1.51.5 × 10⁻⁴= 4.5 × 10⁻³m = 4.5 mm . Result: The computed value matches expected outcome and confirms correct choice as per NCERT.