The Total solution for NCERT class 6-12
In a Young’s double-slitexperiment, the slits are separated by 0.28 mm and the screen is placed 1.4 maway. The distance between the central bright fringe and the fourth brightfringe is measured to be 1.2 cm. Determine the wavelength of light used in theexperiment.
Distance between the slits, d = 0.28 mm = 0.28 × 10−3 m
Distancebetween the slits and the screen, D =1.4 m
Distancebetween the central fringe and the fourth (n =4) fringe,
u = 1.2 cm = 1.2 × 10−2 m
In caseof a constructive interference, we have the relation for the distance betweenthe two fringes as:
Where,
n = Order of fringes = 4
λ =Wavelength of light used
∴
Hence, the wavelength of thelight is 600 nm.