The ratio of the absorbed sound energy Ea E_a\,Ea to the incident sound energy Ei E_i\,Ei is known as the sound absorption coefficient, α\alphaα:
α=EaEi \alpha = \frac{E_a}{E_i} α=EiEaThe table below shows the sound absorption coefficient for various surface materials used in building design.
| Material | Sound absorption coefficient (α\alphaα) |
|---|---|
| Concrete wall | 0.02 |
| Glass window | 0.05 |
| Cork floor tiles | 0.45 |
| Acoustic foam panels | 0.85 |
Explain why a video-recording studio lined with acoustic foam panels and cork floor tiles is much quieter and has less echo than an untreated room with concrete walls and large glass windows.
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.