Answer:
0.006 m
Explanation:
d = separation between the slits = 0.150 mm = 0.150 x 10⁻³ m
λ = wavelength of the light = 643 nm = 643 x 10⁻⁹ m
D = distance of the screen where interference pattern is observed = 140 cm = 1.40 m
δ = Path difference
Path difference is given as
δ = Dλ/d
δ = (1.40) (643 x 10⁻⁹)/(0.150 x 10⁻³)
δ = 0.006 m