O Levels Physics (5054)•5054/12/M/J/18
Explanation
Human audible frequency range
Steps:
- Recall standard human hearing range: 20 Hz to 20 kHz for healthy adults.
- Compare A (12 Hz): Below 20 Hz threshold.
- Compare B (12 Hz): Identical to A, below threshold.
- Compare C (12 kHz): Within 20 Hz to 20 kHz.
- Compare D (12 MHz): Far exceeds 20 kHz upper limit.
Why C is correct:
- 12 kHz lies within the defined audible spectrum of 20 Hz to 20 kHz, per physiological acoustics.
Why the others are wrong:
- A: 12 Hz is infrasonic, undetectable by human ears.
- B: 12 Hz matches A, infrasonic and inaudible.
- D: 12 MHz enters radio wave frequencies, ultrasonic and inaudible.
Final answer: C
Topic: Sound
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