What kind of interference occurs when waves are out of phase?

Destructive interference occurs when waves are out of phase, meaning that the peaks of one wave align with the troughs of another wave. This results in the cancellation of the waves, leading to a reduction in the overall amplitude of the resulting wave. When two waves with the same frequency and amplitude are perfectly out of phase (180 degrees apart), they can completely neutralize each other, resulting in zero amplitude at that point. This principle is significant in ultrasound and other wave phenomena, as it helps to understand how wave interactions can affect image quality and signal strength.

The other types of interference mentioned will not produce this canceling effect. Constructive interference occurs when waves are in phase and their amplitudes add together, resulting in greater overall amplitude. Sympathetic interference and resonant interference do not fit the definition of out-of-phase wave interaction and describe different wave behaviors that do not involve cancellation.