Answer:
L = 2.1 m
Explanation:
From Young's Double Slit Experiment, the formula for the distance between two consecutive dark or bright fringes, called fringe spacing, is derived as:
Δx = λL/d
where,
Δx = distance between first and second dark fringe = 4 mm = 4 x 10⁻³ m
λ = wavelength of light = 575 nm = 5.75 x 10⁻⁷ m
d = distance between the slits = 0.3 mm = 3 x 10⁻⁴ m
L = Distance from slits to screen = ?
Therefore,
4 x 10⁻³ m = (5.75 x 10⁻⁷ m)(L)/(3 x 10⁻⁴ m)
L = (4 x 10⁻³ m)/(1.92 x 10⁻³)
L = 2.1 m
