Two coherent monochromatic light beams have an intensity ratio of . When these beams interfere, what is the ratio of maximum intensity to minimum intensity () in the resulting fringe pattern?

Answer and explanation

Correct answer: D.

  1. Step 1: Relate intensity to wave amplitudes: .
  2. Step 2: The maximum and minimum amplitudes are , and .
  3. Step 3: Compute the intensity ratio: .
Answer
.
Why not the others: is the ratio of individual beam intensities; uses ; forgets to square the amplitude ratio.

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