Geophysicists use low-frequency acoustic transmitters to study tectonic activity beneath the ocean floor. In seawater, where the speed of sound is 1500 m s-1, one of these transmitters emits a continuous, sinusoidal acoustic wave.
Which of the following wavelengths of this wave in seawater would classify it as infrasound?
7.5 mm7.5\text{ mm}7.5 mm
75 cm75\text{ cm}75 cm
7.5 m7.5\text{ m}7.5 m
120 m120\text{ m}120 m
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.