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Double-slit experiment: fringe widths (one wavelength)


A double-slit experiment is setup with two slits 0.8 mm apart and the screen placed 70 cm from the plane of the slits.
When monochromatic light is shone on the slits, it's seen that the tenth bright fringe is 5.6 cm from the central bright fringe.
What is the wavelength of the light?
Note: Input answer in units of nm.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi