GCSE Physics resources

AQA GCSE Waves

Wave Properties, Speed, Frequency and Wavelength

Use the wave equation v = fλ and label amplitude, wavelength, frequency and direction. A change in frequency at a fixed speed changes wavelength, while amplitude describes energy transfer rather than spacing.

AQA 8463AQA 8464 GCSE PhysicsCombined Science: Trilogy FoundationHigher

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The revision snapshot

Use the wave equation v = fλ and label amplitude, wavelength, frequency and direction. A change in frequency at a fixed speed changes wavelength, while amplitude describes energy transfer rather than spacing.

By the end, you should be able to:

  • Keep the wave quantities separate.
  • Apply the waves model, evidence or method to an unfamiliar exam context.
  • Recognise and correct this wrong turn: Measuring wavelength crest to trough.

Before you revise

Diagnostic question

Choose an answer from memory. Your result tells you what to watch for in the guide.

Which statement correctly summarises wave properties, speed, frequency and wavelength?

Core revision guide

Learn the model, then use it

Wave Properties, Speed, Frequency and Wavelength questions become manageable when the central model, evidence and exam method are kept together. Read the explanation, test the misconception and then apply the idea without looking back.

Keep the wave quantities separate

Use the wave equation v = fλ and label amplitude, wavelength, frequency and direction. A change in frequency at a fixed speed changes wavelength, while amplitude describes energy transfer rather than spacing.

Build the physics picture

Wavelength is the distance between two matching points, such as adjacent crests; frequency is the number of waves each second. For a fixed wave speed, higher frequency means shorter wavelength. Amplitude is a maximum displacement and relates to energy transfer, not speed.

Relationships used in this guide

Wave speed: v = fλ (m/s, Hz, m). Period: T = 1 ÷ f (s, Hz). Choose each relationship from the physical change described, convert quantities into compatible units and keep the unit beside the final answer.

A transverse wave labels equilibrium, amplitude and wavelength beside a longitudinal wave with compression and rarefaction.
Amplitude is measured from equilibrium; particle oscillation is parallel to travel for a longitudinal wave.Open the full-size exam diagram
Wave speedv = fλm/s, Hz, m
PeriodT = 1 ÷ fs, Hz

Misconception clinic

Replace the tempting answer

Read each belief, say what is wrong with it, then compare your correction.

Tempting idea: Measuring wavelength crest to trough.

Use instead: Use the wave equation v = fλ and label amplitude, wavelength, frequency and direction. A change in frequency at a fixed speed changes wavelength, while amplitude describes energy transfer rather than spacing.

Tempting idea: Using amplitude as wave speed.

Use instead: Wavelength is the distance between two matching points, such as adjacent crests; frequency is the number of waves each second. For a fixed wave speed, higher frequency means shorter wavelength. Amplitude is a maximum displacement and relates to energy transfer, not speed.

Tempting idea: Mixing Hz and seconds.

Use instead: Read the diagram, convert units, choose v = fλ and use the wording in the question to describe the physical change.

Retrieval practice

Quick checks

1. Which exam method is most reliable for wave properties, speed, frequency and wavelength?

2. Which statement correctly applies wave properties, speed, frequency and wavelength to a question?

3. A pupil writes: “Measuring wavelength crest to trough.” Which replacement is accurate?

Explore the relationship

Wave equation explorer

Change frequency or wavelength, then calculate wave speed using v = fλ.

What to notice: use the readout to describe how one variable changes when the other is controlled.

Worked examples

See the method being built

These examples expose the difference between a secure keep the wave quantities separate method and the common error “Measuring wavelength crest to trough.”.

Example 1 · Wave equation

A wave has frequency 5.0 Hz and wavelength 0.80 m. Find speed.

  1. Use v = fλ.
  2. Multiply 5.0 × 0.80.
  3. Give m/s.
Show the answer

v = 4.0 m/s.

Example 2 · Find wavelength

A wave speed is 340 m/s and frequency 170 Hz. Find wavelength.

  1. Rearrange λ = v/f.
  2. 340 ÷ 170.
  3. Give metres.
Show the answer

λ = 2.0 m.

Example 3 · Amplitude meaning

Two waves have same frequency but one larger amplitude. State the difference.

  1. Keep frequency unchanged.
  2. Identify displacement.
  3. Link amplitude to energy transfer.
Show the answer

The larger-amplitude wave has greater maximum displacement and typically transfers more energy.

Exam precision

Exam technique: Keep the wave quantities separate

Do this: Read the diagram, convert units, choose v = fλ and use the wording in the question to describe the physical change.

Independent practice

Exam-style questions

Write an answer before opening the marking guidance. Then edit the exact phrase or step that would gain the next mark.

1. Define wavelength.

[2 marks]
Show marking guidance and model answer

Marking guidance: 2 marks are available for relevant, linked physics points that match the model answer.

Model answer: Distance between two adjacent points in phase, such as crest to crest.

2. Define frequency.

[2 marks]
Show marking guidance and model answer

Marking guidance: 2 marks are available for relevant, linked physics points that match the model answer.

Model answer: Number of complete waves passing a point each second.

3. State the unit of frequency.

[1 mark]
Show marking guidance and model answer

Marking guidance: Award one mark for the precise statement shown in the model answer.

Model answer: Hertz, Hz.

4. A 12 Hz wave has wavelength 0.50 m. Find speed.

[3 marks]
Show marking guidance and model answer

Marking guidance: Award one mark for the correct relationship, one for a valid substitution and one for the final answer with its unit.

Model answer: v = 12 × 0.50 = 6.0 m/s.

5. Explain what amplitude measures.

[3 marks]
Show marking guidance and model answer

Marking guidance: Award up to 3 marks for distinct physics points joined into a clear cause-and-effect chain.

Model answer: Maximum displacement from the equilibrium position.

6. If speed stays constant and frequency doubles, state what happens to wavelength.

[2 marks]
Show marking guidance and model answer

Marking guidance: 2 marks are available for relevant, linked physics points that match the model answer.

Model answer: It halves.

Questions pupils ask

Wave Properties, Speed, Frequency and Wavelength FAQs

What is the main idea in Wave Properties, Speed, Frequency and Wavelength?

Use the wave equation v = fλ and label amplitude, wavelength, frequency and direction. A change in frequency at a fixed speed changes wavelength, while amplitude describes energy transfer rather than spacing.

What mistake should I avoid in Wave Properties, Speed, Frequency and Wavelength?

Measuring wavelength crest to trough. Wavelength is the distance between two matching points, such as adjacent crests; frequency is the number of waves each second. For a fixed wave speed, higher frequency means shorter wavelength. Amplitude is a maximum displacement and relates to energy transfer, not speed.

Useful next steps

Connect this guide to your next task

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