Frequency of a sound wave is determined by the ______.

Frequency of a sound wave is determined by the ______.

• A. The source only
• B. The observer's ear
• C. The environment's humidity
• D. The medium's density

Answer: (A)

Frequency is determined by the source that produces the sound—the rate at which the source oscillates. This frequency stays the same as the sound travels, even when it moves into a different medium. What changes with the medium is the speed of sound and the wavelength, not the frequency. The observer’s ear just detects that frequency as pitch, while humidity or the medium’s density can affect how fast sound travels and how much it attenuates, but they don’t set the pitch. So the frequency is determined by the source only.

Frequency is determined by the source that produces the sound—the rate at which the source oscillates. This frequency stays the same as the sound travels, even when it moves into a different medium. What changes with the medium is the speed of sound and the wavelength, not the frequency. The observer’s ear just detects that frequency as pitch, while humidity or the medium’s density can affect how fast sound travels and how much it attenuates, but they don’t set the pitch. So the frequency is determined by the source only.