Suppose a water wave arises in point A on a water surface and expands to point B. In point B a water wave is created simultaneously, however, with an amplitude 1000 times greater than that in point A. An interference pattern will then arise between these 2 points A and B. But I wonder if the wave coming from Point A would have its energy measurable in Point B or in a very small area around B. So I wonder if the relatively small energy propagated by wave A would still be point can reach B or is it swallowed, as it were, by the much larger wave from point B? Is there interference or not?
Answer
As long as you stay in the linear regime (that is, the speed of the waves does not depend on their amplitude) you have interference, which is also the ratio between the amplitudes of the two waves.
It is of course possible that you cannot ‘measure’ the small wave. To measure you need some kind of measuring instrument. A device that can measure ‘large’ amplitudes is usually not very sensitive and a sensitive device quickly becomes overdriven if the amplitude becomes too large. So it is often difficult to measure large and small amplitudes together. But this is a measurement problem.
Answered by
Prof Walter Lauriks
Physics Acoustics
Old Market 13 3000 Leuven
https://www.kuleuven.be/
.