A wildlife conservation group uses an acoustic beacon that emits sound at a frequency of 15 Hz to guide herd movements.
Explain why this signal can be detected by elephants but cannot be heard by the human conservationists operating the device.
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.