Question

In a Young’s Double Slit Experiment, distance between slits and screen is D. 3rd maximum is formed at a distance y from central maximum. Now, the screen is displaced by x along perpendicular bisector of slits. If 2nd minimum is now formed at same distance y from central maximum then x is

(a) D/2 towards slits

(b) 2D away from slits

(c) D/4 towards slits

(d) D away from slits

Answer 1

Correct option: (d) D away from slits

Explanation: 

Suppose fringe width is changed from w to w’.

3w'/2 = 3w

Therefore, displacement of screen x = D’ – D = 2D – D = D.