Q131 / 180 · AIIMS 2002 · Physics

What is the path difference for destructive interference?

  • A
    $n \lambda$
  • B
    $\frac{(n+1) \lambda}{2}$
  • C
    $n(\lambda+1)$
  • Correct answer
    D
    $\frac{(2 n+1) \lambda}{2}$.

Solution

If the waves interfere destructively, then path difference is given by $\frac{\lambda}{2}, \frac{3 \lambda}{2}, \frac{5 \lambda}{2}$ etc. Therefore path difference of a destructive interference is $\frac{(2 n+1) \lambda}{2}$ (where $\left.n=1,2,3, \ldots\right)$ etc.

Hence, the correct answer is option: 'D'.

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