Question Detail
Question
One beam of coherent light travels path P_1 in arriving at point Q and another coherent beam travels path P_2 in arriving at the same point. If these two beams are to interfere destructively, the path difference |P_1 - P_2| must be equal to
Correct Answer
Option A is the correct answer.
Detailed Explanation
For two coherent waves to interfere destructively, their phase difference must be an odd multiple of π radians (180°). This corresponds to a path difference (Δx) that is an odd multiple of half-wavelengths (λ/2).Mathematically, the condition for destructive interference is:Δx = (n + 1/2)λ, where n = 0, 1, 2, ...This can be written as Δx = (1/2)λ, (3/2)λ, (5/2)λ, and so on, which means an odd number of half-wavelengths.
Hint
Recall the conditions for constructive and destructive interference in terms of path difference.