Answer:
d = [tex]\frac{nLembda}{sin(theta)}[/tex]
Explanation:
This comes from diffrection pattern equation used to locate fringe pattern, i will explain every variable in it here.
n = order of fringe = 0 1 2 3 .. and negative integars as well.
d is sacing between slits.
Theta = angle at which light-Ray is directed towards fringe.
It appears that the distance between consectice fringes would same as the distance between two slits 'd'.
therefore calculating that distance should give us the distance between two fringe patters.
Note we don't use transversal seperation distance here.