Statement I : The pitch of the sound wave depends upon its frequency Statement I : The loudness of the sound wave depends upon its amplitude

Statement I is true because the pitch of a sound is the brain's perception of its frequency; higher frequencies result in higher pitches, while lower frequencies produce lower pitches [2]. Statement II is also true because the loudness or volume of a sound is determined by the amplitude of the sound wave. A larger amplitude corresponds to a louder sound, whereas a smaller amplitude results in a softer sound. While both statements accurately describe fundamental properties of sound waves, Statement II is not the explanation for Statement I. Pitch and loudness are independent subjective properties related to different physical characteristics of the wave—frequency and amplitude, respectively. Therefore, while both are individually correct, the amplitude-loudness relationship does not explain why frequency determines pitch.

Sources

1. [1] https://www.nps.gov/subjects/sound/understandingsound.htm
2. [2] https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/doppler.html