In fog, a lightship warns nearby ships by sounding a horn in the air and striking a bell under the water at the same instant. A ship 1020 m from the lightship detects the bell with an underwater microphone and the horn with a microphone on its deck.
The speed of sound is 340 m/s in air and 1500 m/s in seawater.
Calculate the time interval between the ship detecting the bell and detecting the horn.
112 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.