Which describes constructive interference?

Which describes constructive interference?

• A. Sound waves are in phase and the resulting amplitude is decreased.
• B. Sound waves are out of phase and the resulting amplitude is increased.
• C. Sound waves are in phase and the resulting amplitude is increased.
• D. Sound waves are out of phase and the resulting amplitude is decreased.

Answer: (C)

Constructive interference happens when waves meet in step, so their peaks align with peaks and troughs align with troughs. When they combine, their displacements add, giving a resultant amplitude that is the sum of the two. For sound, this means a louder result because the amplitudes reinforce each other. If the waves are out of phase, their peaks don’t line up with peaks, and they can partially or wholly cancel, producing a smaller amplitude. So, in-phase alignment with an increased resulting amplitude is the hallmark of constructive interference.

Constructive interference happens when waves meet in step, so their peaks align with peaks and troughs align with troughs. When they combine, their displacements add, giving a resultant amplitude that is the sum of the two. For sound, this means a louder result because the amplitudes reinforce each other. If the waves are out of phase, their peaks don’t line up with peaks, and they can partially or wholly cancel, producing a smaller amplitude. So, in-phase alignment with an increased resulting amplitude is the hallmark of constructive interference.