Final answer:
The lowest frequency at which destructive interference occurs is the antiresonance frequency, where wave amplitudes cancel out, leading to minimal sound intensity.
Step-by-step explanation:
The lowest frequency at which destructive interference occurs is referred to as the antiresonance frequency. Destructive interference results in the cancellation of wave amplitudes when two waves of the same frequency and opposite phase meet. In a system like a pipe resonator, this would mean the intensity of the sound at the antiresonance frequencies would be the least. It is important to differentiate between antiresonance frequency and the resonance frequency, which is the frequency at which constructive interference causes the wave amplitudes to reinforce each other, leading to standing waves and enhanced sound levels.
Sound interference is a phenomenon that can be observed in various areas, including musical instruments. Resonance, due to sound resonances, is a result of the constructive and destructive interference of sound waves. The resonant frequencies interfere constructively to create standing waves and thus are present at resonant conditions in instruments or objects. In contrast, other frequencies that do not meet these conditions will interfere destructively and be absent or reduced in intensity.