# A student is investigating sound waves travelling through air. Explain what is meant by the terms amplitude, frequency, and wavelength, and describe how the speed of a wave is related to its frequency and wavelength.

> Eduqas A-Level Physics — 3.1 Wave properties · Explain · 5 marks

> Sound waves are longitudinal waves that transfer energy through a medium without transferring matter.

## Mark scheme (5 marks)

1. Amplitude is the maximum displacement of a particle from its rest/equilibrium position
2. Frequency is the number of complete waves (cycles) passing a point per second
3. Wavelength is the distance between two successive points that are in phase / the length of one complete wave cycle
4. Wave speed equals frequency multiplied by wavelength (v = fλ)
5. For a fixed wave speed, frequency and wavelength are inversely proportional / if frequency increases, wavelength decreases (and vice versa)

## Key terms

- [amplitude](https://www.gradenine.co.uk/glossary/amplitude)
- [frequency](https://www.gradenine.co.uk/glossary/frequency)
- [wavelength](https://www.gradenine.co.uk/glossary/wavelength)

## Related

- [Revision notes for Eduqas A-Level Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-is-investigating-sound-waves-522c34f9) · Published by Druglandscape Ltd.