Double-slit experiment (path length)

[PhysicsFTW22]

Homework Statement

In a double slit-experiment, how far apart do the path length differences have to be to get a pattern with adjacent constructive and destructive interference fringes?

I have no clue how to even begin this problem.

 

[PhysicsFTW22]

Does anyone know this? I really need to find out :(.

 

[bayan]

Homework Statement

In a double slit-experiment, how far apart do the path length differences have to be to get a pattern with adjacent constructive and destructive interference fringes?

I have no clue how to even begin this problem.

Constructive interference occurs when Δλ is a whole integer(0(central maximum),1,2,3 etc..) and destructive interference occurs when Δλ is a whole integer + half (0.5, 1.5, 2.5 etc..)

hope it helps out.