Answer:
Explanation:
The path length difference = extra distance traveled
The destructive interference condition is:
[tex]\Delta d = (m+1/2)\lambda[/tex]
where m =0,1, 2,3........
So, ←
[tex]\Delta d = (m+1/2)\lamb da9/tex]
so [tex]\Delta d = \frac{\lambda}{2}[/tex]
⇒ λ = 2Δd = 2×10 = 20