Question

What is interference derive formula of fringe width?

Answer 1

Explanation:

Let d = distance between the slits (two sources). P = a point at a distance from the middle of the screen where a bright fringe is formed. S2P – S1P = nλ where n = 0,1,2,3……. Since the fringes are equally spaced the distance between two consecutive bright or consecutive dark fringes gives fringe width.