Answer:
Y = 5.03 x 10⁻³ m = 5.03 mm
Explanation:
Using Young's Double-slit formula:
[tex]Y = \frac{\lambda L}{d}[/tex]
where,
Y = Fringe Spacing = Width of bright fringe = ?
λ = wavelength = 633 nm = 6.33 x 10⁻⁷ m
L = Screen distance = 3.1 m
d = slit width = 0.39 mm = 3.9 x 10⁻⁴ m
Therefore,
[tex]Y = \frac{(6.33\ x\ 10^{-7}\ m)(3.1\ m)}{3.9\ x\ 10^{-4}\ m}[/tex]
Y = 5.03 x 10⁻³ m = 5.03 mm
