Answer:
Destructive interference
Step-by-step explanation:
When two waves superpose one each they produce a resultant wave. This phenomenon is known as interference. The resultant amplitude of one wave's crest of meets the other wave's crest or vice-versa is the sum of the individual amplitudes. This is constructive interference. The resultant amplitude of the waves whose crest of one wave meets the trough of the other wave is the difference of the individual amplitudes. This is destructive interference.