In Young's double slit experiment, what is the path difference Delta x for constructive interference (bright fringe)?

Answer and explanation

Correct answer: A. n lambda

  1. Step 1: Constructive interference occurs when waves arrive in phase. Step 2. The path difference must be an integer multiple of the wavelength: Delta x = n lambda (where n = 0, 1, 2, ...). Answer: n lambda. Why not the others: (2n + 1) lambda / 2 is the condition for destructive interference (dark fringe); (n + 1/2) lambda is dark fringe; (2n - 1) lambda is odd wavelengths.

Practise more Waves, Thermodynamics and Optics.

Free questions with an explanation for every one, and full timed Higher Secondary Certificate Examination (Bangladesh) mock tests.