Table 1 shows the depth of a lake, measured using ultrasound pulses, at various distances from a jetty.
| Distance from jetty (m) | Depth of the lake (m) |
|---|---|
| 0 | 0.0 |
| 20 | 3.2 |
| 40 | 6.5 |
| 60 | 8.0 |
| 80 | 10.5 |
| 100 | 13.0 |
| 120 | 15.5 |
| 140 | 18.0 |
| 160 | 19.5 |
A researcher on a survey boat uses ultrasound pulses to measure the depth of the lake when the boat is positioned exactly 140 m from the jetty.
Calculate the total round-trip time of travel for the ultrasound pulse key to this measurement.
The speed of the ultrasound pulse in the lake water is 1500 m/s.
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.