A survey boat uses an echo sounder to measure the depth of water in a harbour.
First, the crew find the speed of sound in the harbour water. An underwater microphone is placed 14.8 m from the sounder, and a pulse from the sounder reaches the microphone 10.0 ms after it is sent.
The sounder then sends a pulse straight down. The echo from the seabed is detected 25.0 ms after the pulse is sent.
Calculate the depth of the seabed below the sounder.
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.