Given : D = 2m, d = 2mm, λ1 = 12000 ºA, λ2=10000 ºA
Let n1 be the fringe of slit 1 coinciding with the fringe n2 coming from another slit.
Thus, the equation can be written as,
Thus, we can say that 5th fringe coincides with 6th fringe.
Now, the minimum distance is given by,