Question

Two sources give interference pattern which is observed on a screen, D distance apart from the sources. The fringe width is 2β. If the distance D is now doubled, then fringe width will : 

(a) become β 

(b) become β ⁄ 2 

(c) 4β 

(d) remain the same

Answer 1

Correct option (c) 4β

Explanation:

In the interference pattern, the fringe is given by

In second case when the distance is doubled, then