What impact does destructive interference have on wave amplitude?

• A. Increases amplitude
• B. Decreases amplitude
• C. Has no effect
• D. Changes frequency

Answer: (B)

Destructive interference occurs when two waves meet in such a way that their displacements oppose each other. When this happens, the amplitude of the resultant wave is the difference in amplitudes of the individual waves. If two waves of equal amplitude are perfectly out of phase, they can cancel each other out completely, resulting in a wave of zero amplitude. Therefore, destructive interference leads to a decrease in amplitude, which is why the answer is that it decreases amplitude.

Other options do not accurately describe the effect of destructive interference—amplitude cannot be increased through destructive interference, nor does it leave amplitude unchanged or alter the frequency of the waves involved. The phenomenon is specifically about the interaction of the waves’ amplitudes.