The ratio of the reflected ultrasound energy Er E_r\,Er to the incident ultrasound energy Ei E_i\,Ei is known as the ultrasound reflection coefficient, β\betaβ:
β=ErEi \beta = \frac{E_r}{E_i} β=EiErTo study bat echolocation, researchers construct specialized flight-testing chambers. The table below shows the ultrasound reflection coefficient at 40 kHz40\text{ kHz}40 kHz (a typical bat echolocation frequency) for various lining materials.
| Material | Ultrasound reflection coefficient (β\betaβ) |
|---|---|
| Rough felt lining | 0.08 |
| Smooth wooden panels | 0.65 |
| Polished metal sheet | 0.94 |
| Textured rubber tiles | 0.12 |
Explain why a bat flight-testing chamber lined with rough felt lining and textured rubber tiles prevents the bats from becoming disoriented by wall reflections, compared to an untreated chamber with polished metal sheets and smooth wooden panels.
Use information from the table to support your answer.
35 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.