Answer:
Y = 0.0254 m = 25.4 mm
Step-by-step explanation:
The formula for the fringe spacing in Young's Double-slit experiment is given by the following formula:

where,
Y = fringe spacing = 0.0176 m
λ = wavelength = 425 nm = 4.25 x 10⁻⁷ m
L = Distance between screen and slits
d = slit separation
Therefore,

Now, for:
λ = 614 nm = 6.14 x 10⁻⁷ m

Y = 0.0254 m = 25.4 mm