Question

In Young's double slit experiment, the distance of the $n^{th}$ dark fringe from the centre is:

• A. $n\left(\frac{\lambda D}{2d}\right)$
• B. $n\left(\frac{2D}{\lambda d}\right)$
• C. $(2n-1)\left(\frac{\lambda D}{2d}\right)$
• D. $(n-1)\left(\frac{4D}{\lambda d}\right)$

Answer 1

The correct option is C $(2n-1)\left(\frac{\lambda D}{2d}\right)$

Position of the $n^{th}$ dark fringe is at a distance of

$y=(2n-1)\frac{\lambda D}{2d}$ from the center

where

$\lambda :\text{Wavelength}$

$D:\text{Distance betwee slits}$

$d:\text{slit width}$