Sound Trace: Decreasing Amplitude with Increasing Frequency

Steps:

• Recall pitch corresponds to frequency, shown by closer wave spacing on the trace.
• Recall loudness corresponds to amplitude, shown by wave height.
• Examine traces for decreasing height as spacing tightens.
• Select the trace matching quieter sound (lower amplitude) at higher pitch (higher frequency).

Why C is correct:

• Option C shows amplitude decreasing as frequency increases, per the inverse relationship where higher pitch waves have smaller heights, defining quieter sound.

Why the others are wrong:

• A: Amplitude increases with frequency, indicating louder sound at higher pitch.
• B: Constant amplitude despite changing frequency, so loudness unchanged.
• D: Amplitude decreases but frequency stays constant, so pitch unchanged.

Final answer: C