Question Detail
Question
One beam of coherent light travels path P, in arriving at point Q and another coherent beam travels path Q, in arriving at the same point. If these two beams interfere destructively, the path difference |P - Q| must be equal to
Correct Answer
Option A is the correct answer.
Detailed Explanation
For two coherent light beams to interfere destructively, their path difference must be an odd multiple of half-wavelengths. That is, Path Difference = (m + 1/2)λ, where m = 0, 1, 2, ... This ensures that the waves arrive completely out of phase.
Hint
Recall the conditions for destructive interference in terms of path difference and wavelength.