Sonography Canada Physics Core Practice Exam

The amplitude of a sound wave is primarily determined by the sound source itself. The sound source generates vibrations that create pressure variations in the surrounding medium, which are perceived as sound waves. The amplitude reflects the maximum displacement of particles in the medium from their rest position due to these vibrations, influencing the loudness of the sound. A greater amplitude corresponds to a louder sound, while a smaller amplitude results in a softer sound.

The other factors listed, such as frequency, density of the medium, and temperature, can influence other characteristics of sound waves but do not directly determine amplitude. Frequency relates to the pitch of the sound, density affects how sound propagates through a medium, and temperature can influence the speed of sound but not the amplitude directly. Hence, the correct answer emphasizes the importance of the sound source in determining amplitude.