A student investigates how a solid membrane responds to sound. The sound amplitude at the membrane is kept constant.
The table shows two results.
| Frequency in Hz\mathrm{Hz}Hz | Membrane amplitude in mm\mathrm{mm}mm |
|---|---|
| 1000 | 0.60 |
| 30 00030\,00030000 | 0.02 |
The student concludes that the source produces no sound at 30 000 Hz30\,000\ \mathrm{Hz}30000 Hz.
Which evaluation of the conclusion is correct?
It is supported because equal sound amplitudes must always produce equal membrane amplitudes.
It is unsupported because the membrane must increase the frequency of every sound it receives.
It is unsupported because a small response can result from the membrane's frequency limit.
It is supported because sound above the hearing limit cannot travel through the surrounding air.
112 exam-style questions on Edexcel GCSE Physics 4.3 Sound, ultrasound and infrasound, covering 4.3.1 Sound waves, vibrations and the human ear, 4.3.2 Ultrasound and infrasound, 4.3.3 Uses of ultrasound and infrasound, and 4.3.4 Sound waves passing between media. Each one has a worked solution and a mark scheme showing where the marks go.