An ultrasonic distance sensor is fixed above a metal plate. The plate is raised towards the sensor in equal steps. At each position the plate is held still, and the sensor sends one pulse through the air towards the plate and detects the reflected pulse.
The speed of ultrasound in air is 340 m/s.
| Position number | Echo time in ms\mathrm{ms}ms |
|---|---|
| 1 | 18.0 |
| 2 | 17.4 |
| 3 | 16.8 |
| 4 | 16.2 |
The plate continues to be raised by the same step each time. Calculate the distance between the sensor and the plate at position 6.
112 exam-style questions on Edexcel GCSE Physics 4.1 Wave properties, covering 4.1.1 Waves transfer energy and information, 4.1.2 Frequency, wavelength, amplitude, period and wavefronts, 4.1.3 Longitudinal and transverse waves, 4.1.4 The wave speed equations, 4.1.5 Measuring wave velocity, and 4.1.6 Calculating depth or distance from waves. Each one has a worked solution and a mark scheme showing where the marks go.