Answer:
The letters indicating the fringes is AD
Explanation:
The waves that differ is:
Δx = 2λ
The equation for phase difference is:
[tex]delta\phi =\frac{2\pi }{\lambda } deltax=\frac{2\pi }{\lambda } 2\lambda =4\pi[/tex]
The constructive interference is equal:
ΔΦ = 2nπ
If
n = 0, central bright fringe
n = ±1, first maxima on both fringes
n = ±2, second maxima on both fringes
The conclusion is that ΔΦ = 4π means to A and D bright fringes, so, the answer is AD
