10.4 In Young’s double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Determine the wavelength of light used in the experiment.
Step 1: Find the wavelength of light used in the experiment.
Distance between the slits and the screen, D = 1.4 m
and the distance between the slits, d = 0.28 mm = 0.28 x 10-3 m
Distance between the central fringe and the fourth (n = 4) fringe, u = 1.2 cm = 1.2 × 10-2 m
As u=nλDd
⇒λ=udnD=1.2×10−2×0.28×10−34×1.4=6×10−7 m=600 nm
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