Which description matches destructive interference?

• A. Constructive interference
• B. Interference
• C. Diffraction
• D. Destructive interference

Answer: (D)

Destructive interference happens when two waves overlap with opposite phases, so their displacements cancel each other out and the total amplitude is reduced, sometimes reaching zero. This is a specific outcome within interference, where the waves subtract rather than add. The opposite case is constructive interference, where the waves are in phase and their amplitudes reinforce each other to produce a larger amplitude. Diffraction is about the spreading and bending of waves around obstacles and can produce interference patterns, but it’s not the description of cancellation itself. Interference, in general, covers both constructive and destructive outcomes, so the description that directly captures the cancellation behavior is destructive interference.