When two sound waves interfere in phase, what is the result?

• A. Destructive interference
• B. Standing waves
• C. Increased amplitude
• D. Natural frequency

Answer: (C)

When two sound waves interfere in phase, the result is indeed an increase in amplitude. In-phase interference occurs when the peaks and troughs of the two waves align perfectly, adding together constructively. This results in a combined wave that has a greater amplitude than either of the individual waves.

This increase in amplitude is a key concept in wave behavior. When two waves with the same frequency and phase meet, their effects strengthen each other, which leads to louder sounds in the context of sound waves. This principle also underlies many acoustic phenomena, including how sound reinforcement systems amplify sound in performance spaces.

The other provided choices address different concepts. For example, destructive interference occurs when sound waves are out of phase, leading to a reduction in amplitude. Standing waves can occur under certain conditions when waves reflect and interfere, but they are not a direct result of in-phase interference specifically. Natural frequency refers to the frequency at which a system naturally oscillates and is not directly related to wave interference.