Answer & explanation
Correct answer: option 3
$\text{For first destructive interference the path difference is equal to }\pm \frac{\lambda}{2}$
$\text{Path difference between two paths is } \lambda$
Correct answer: option 3
$\text{For first destructive interference the path difference is equal to }\pm \frac{\lambda}{2}$
$\text{Path difference between two paths is } \lambda$