# In Young’S Double Slit Experiment, Using Monochromatic Light, Fringes Are Obtained on a Screen Placed at Some Distance from the Slits. If the Screen is Moved by 5 X 10-2 M Towards - Physics (Theory)

Sum

In Young’s double-slit experiment, using monochromatic light, fringes are obtained on a screen placed at some distance from the slits. If the screen is moved by 5 x 10-2 m towards the slits, the change in the fringe width is 3 x 10-5 m. If the distance between the two slits is 10-3 m, calculate the wavelength of the light used.

#### Solution

Here, ΔD = 5 x 10-2 m, Δβ = 3 ×10-5 m, d = 10-3 m, λ = ?
We know that fringe width in Young’s double-slit experiment is given by

"β" = λ "D"/"d"

Here, since λ and d are constant, we can write

"Δβ" = λ/"d" "ΔD"

∴ λ = "Δβ"/"ΔD" d

λ = ( 3 xx 10^-5 xx 10^-3)/(5 xx 10^-2)

λ = 0.6 xx 10^-6 m xx 10^-7 m = 6000Å

Concept: Interference of Light Waves and Young’s Experiment
Is there an error in this question or solution?