An ultrasonic sensor is fixed to the base of a storage tank. The tank contains water 2.4 m deep, with a layer of oil floating on top of the water.
The sensor sends a sound pulse vertically upwards. The pulse travels through the water at 1500 m/s and through the oil at 1300 m/s. It reflects from the top surface of the oil and returns to the sensor. The total time between sending the pulse and detecting its reflection is 4.2 ms.
Calculate the thickness of the oil layer.
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.