Answer:
d = 1.51 x 10⁻⁵ m = 15.1 μm
Explanation:
We will use young's Double Slit formula here:
[tex]Y = \frac{\lambda L}{d}\\\\d = \frac{\lambda L}{Y}[/tex]
where,
d = width of strand = ?
λ = wavelength = 631.8 nm = 6.318 x 10⁻⁷ m
L = Screen to hair distance = 1.2 m
Y = fringe spacing = 5.02 cm = 0.0502 m
Therefore,
[tex]d = \frac{(6.318\ x\ 10^{-7}\ m)(1.2\ m)}{0.0502\ m}[/tex]
d = 1.51 x 10⁻⁵ m = 15.1 μm