What does an increase in amplitude affect in a sound wave?

An increase in amplitude of a sound wave directly influences both amplitude and intensity. Amplitude refers to the maximum extent of a vibration or oscillation, which in sound waves correlates to loudness. When amplitude is increased, the wave becomes louder, as it represents greater energy output from the sound source.

Intensity, on the other hand, is defined as the power per unit area and is directly related to the amplitude of the wave. Specifically, intensity is proportional to the square of the amplitude. Therefore, as the amplitude increases, the intensity levels will also rise because the energy carried by the wave increases. In essence, increasing the amplitude enhances both the energy that the wave carries and the perceived loudness, reinforcing the relationship between these two properties in acoustics.

The other potential choices do not capture this direct relationship. For instance, stating that wavelength is affected by amplitude would not reflect how these parameters connect, as wavelength primarily is determined by the frequency of the wave rather than its amplitude. Similarly, focusing solely on intensity, without acknowledging the simultaneous change in amplitude, does not give a full picture of how sound waves operate.