GCSE Physics practice questions on sound and ultrasound. Try 3 for free below — with hints, the answer and why the wrong answers are tempting. GCSE Beast has 32 questions on this topic, from first steps to the hardest exam-style problems.
A geology student on a rocky coast looks up the speed of sound in the air, in sea water and in granite rock. Each row of the table gives three speeds in m / s.
Which row gives the most likely values?
| air | sea water | granite | |
|---|---|---|---|
| A | 343 | 1530 | 5950 |
| B | 343 | 5950 | 1530 |
| C | 1530 | 343 | 5950 |
| D | 5950 | 1530 | 343 |
A lifeguard blows a whistle at the side of a swimming pool. A swimmer with her head under the water still hears it, because some of the whistle's sound crosses the surface into the pool.
Which row describes how the frequency, the speed and the wavelength of this sound in the pool compare with their values in the air?
| frequency | speed | wavelength | |
|---|---|---|---|
| A | stays the same | increases | increases |
| B | stays the same | increases | decreases |
| C | stays the same | decreases | decreases |
| D | increases | increases | stays the same |
A research ship maps the seabed with a depth sounder, which sends pulses of sound straight down and times the echoes. Above a sunken wreck, the sounder detects an echo from the top of the wreck 30.0 ms after the pulse is sent, and an echo from the seabed next to the wreck 47.0 ms after the pulse is sent. The speed of sound in sea water is 1530 m / s.
How high does the wreck rise above the seabed?