A sensor is fixed to the edge of a circular fish-farm cage of diameter 40 m. It sends an ultrasound pulse through the water along a diameter of the cage towards a shoal of fish. The shoal is 10 m from the opposite edge of the cage. The speed of sound in the water is 1500 m/s.
What is the time between the pulse being sent and the echo from the shoal being detected by the sensor?
0.020 s0.020\ \mathrm{s}0.020 s
0.067 s0.067\ \mathrm{s}0.067 s
0.013 s0.013\ \mathrm{s}0.013 s
0.040 s0.040\ \mathrm{s}0.040 s
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.