A ship uses sonar to find the depth of the sea. It sends a pulse of ultrasound down to the seabed and detects the echo 0.80 s later.
The speed of sound in sea water is 1500 m/s.
Calculate the depth of the sea below the ship.
A submarine is between the ship and the seabed. The echo from the submarine is detected 0.30 s after the pulse is sent.
Calculate the distance between the submarine and the seabed.
Explain why sound, rather than light, is used to explore structures hidden in deep water.
The echo from a muddy seabed is weaker than the echo from a rocky seabed.
Suggest why.
50 exam-style questions on OCR GCSE Physics 8.3 Beyond Earth, covering 8.3.1 Red-shift and the expanding universe, 8.3.2 Evidence for the Big Bang model, 8.3.3 Formation of the Sun and stellar equilibrium, 8.3.4 Radiation emitted by hot bodies, 8.3.5 The solar system and satellites, 8.3.6 Gravity and circular orbits, 8.3.7 Orbital radius and orbital speed, 8.3.8 Radiation balance and the temperature of the Earth, and 8.3.9 Seismic waves and exploring hidden structures. Each one has a worked solution and a mark scheme showing where the marks go.