Answer:
214.3 x 10⁻⁹ m or 214.3 nm
Explanation:
[tex]d[/tex] = slit separation in the experiment = 3.00 x 10⁻⁵ m
[tex]D[/tex] = screen distance from the slits = 2.00 m
[tex]n[/tex] = Order of the bright fringe = 7
λ = Wavelength of the light
[tex]y[/tex] = distance of the bright fringe from the central bright fringe = 10 cm = 0.10 m
Position of the bright fringe is given as
[tex]y = \frac{nD\lambda }{d}[/tex]
[tex]0.10 = \frac{(7)(2)\lambda }{3.00\times 10^{-5}}[/tex]
λ = 214.3 x 10⁻⁹ m
λ = 214.3 nm