A marine research vessel is stationary above a flat seabed to calibrate its sonar equipment. The vertical distance from the transponder to the seabed is measured by another method to be 318 m318\text{ m}318 m. The transponder emits a sound pulse and a sensor records the time taken for the reflected wave to return.
The crew repeats the calibration test three times and records the results in the table below:
| Distance to seabed (m\text{m}m) | Time 1 (s\text{s}s) | Time 2 (s\text{s}s) | Time 3 (s\text{s}s) |
|---|---|---|---|
| 318 | 0.41 | 0.43 | 0.85 |
One of the measurements (Time 3) is anomalous because the pulse reflected off a dense school of fish instead of the seabed.
Calculate the mean time taken for the sound pulse to return from the seabed, using only the suitable values from the table.
Calculate the speed of sound in this seawater. Use your calculated mean time and the equation:
distance travelled=speed×time \text{distance travelled} = \text{speed} \times \text{time} distance travelled=speed×timeGive your answer to 3 significant figures.
43 exam-style questions on OCR GCSE Physics Wave behaviour. Each one has a worked solution and a mark scheme showing where the marks go.