Question

In a Young's double slit experiment, the slits are separated by 0.30 mm and the screen is kept 1.5 m away. The wavelength of light used is 600 nm. Calculate the distance between the central bright fringe and the 4^th dark fringe.

Answer 1

Given d = 0.30 mm = 0.30 × 10⁻³ m

D = 1.5 m

λ = 600 nm = 600 × 10⁻⁹ m

For dark fringe,

`x_n = (2n - 1)/2 (lambdaD)/d`

When n = 4

`x_4 = (8 - 1)/2 (600 xx 10^-9 xx 1.5)/(0.30 xx 10^-3)`

`x_4 = 7/2 (600 xx 10^-9 xx 1.5)/(0.30 xx 10^-9)`

x₄ = 1.05 cm