In a 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.
Here it is given that,
Distance between the slits, d = 0.28 mm = 0.28 × 10 -3 m
Distance between the slits and the screen, D = 1.4 m
Distance between the central fringe and the fourth (n = 4) fringe, u = 1.2 cm = 1.2 × 10 -2 m
For constructive interference, the distance between the two fringes is given by relation: u = nλ D/d
where, n = Order of fringes
wavelength of the light can be given as: λ = ud/nD = 1.2x10-2x0.28x10-3/4x1.4 = 6x10-7 = 600 nm
Hence, the wavelength of the light is 6 x 10 -7 m.
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(b) In what way is diffraction from each slit related to the interference pattern in a double-slit experiment?
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