The amplitude of a sound wave is most closely related to its

• A. Pitch
• B. Loudness
• C. Wavelength
• D. Speed

Answer: (B)

Amplitude describes how large the pressure fluctuations are in the sound wave, which is what your ear interprets as the strength of the sound. When the wave has a larger amplitude, the air particles are pushed farther from their rest position, delivering more energy to the eardrum and producing a louder sensation. Conversely, smaller amplitude means gentler fluctuations and a quieter sound.

Pitch, the perceived highness or lowness of a sound, comes from frequency, not how tall the wave is. Wavelength and speed are linked to the medium and the frequency, but they aren’t determined by amplitude. So while you can have the same pitch at different loudness levels, amplitude specifically governs loudness.