In a two-slit experiment with monochromatic light, fringes are obtained on a screen placed at some distance from the slits. If the screen is moved by towards the slits, the change in fringe width is
. If the distance between the slits is
,The wave length of the light used is:
We know that fringe width is given by :
In the given problem, wavelength and separation between the slits
is fixed. The fringe width changes due to a change of D (distance of screen from the slits).
Given that .
.