A student uses a microphone connected to an oscilloscope to display two different sound waves, Wave A and Wave B. Wave A has a large amplitude and a low frequency. Wave B has a small amplitude and a high frequency. Describe how the loudness and pitch of Wave A compare with those of Wave B.

Pearson Edexcel International GCSE Physics (4PH1) — 3.3 Light and sound · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

A student investigates two sound waves using a microphone and an oscilloscope. Wave A has a large amplitude and a low frequency. Wave B has a small amplitude and a high frequency.

Model answer (4 marks)

Wave A is louder than Wave B because it has a larger amplitude.
Wave A has a lower pitch than Wave B because it has a lower frequency.

Examiner tips

  • Use the word "louder" for amplitude and "pitch" for frequency. Show the cause–effect link: larger amplitude → louder, lower frequency → lower pitch.
  • Mention both comparisons in separate sentences to use all marks.

Common mistakes

  • Confusing amplitude with frequency. Using "higher" for both amplitude and frequency. Omitting the reason for the comparison.

Mark scheme (4 marks)

  1. Wave A is louder than Wave B
  2. Because Wave A has a greater / larger amplitude (than Wave B)
  3. Wave A has a lower pitch than Wave B
  4. Because Wave A has a lower frequency (than Wave B) / the greater the frequency, the higher the pitch

Key terms in this question

amplitude · frequency · loudness · pitch · oscilloscope · microphone

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