AQA GCSE Combined Science: Trilogy Physics Paper 2 (Foundation), 2024: Question 6

8 marks · Standard Demand difficulty · Extended Answer

Describe a method to investigate the relationship between frequency and wavelength of a wave on a string, identify the wave equation, and calculate wavelength from given frequency and speed.

Practise this question

Question

The image shows a diagram of an experimental setup to investigate waves on a string. A string is connected to a vibration generator, which is powered by a signal generator displaying '45.0'. The string passes over a movable wooden bridge and a pulley, with hanging masses at the end. A metre rule is positioned under the string to measure the wavelength of the stationary wave shown. The question asks for a method to investigate how frequency affects wavelength, to select the correct wave equation from three options, and to calculate wavelength given a frequency of 45.0 Hz and a wave speed of 35.1 m/s.
Question text

06 A teacher demonstrated how the frequency of a wave on a string affects the

wavelength of the wave.

Figure 11 shows the equipment used.

Figure 11

The frequency of the signal generator is adjusted so that the wave shown

in Figure 11 is seen.

At this frequency the string vibrates between the two positions shown in Figure 11.

06.1 Describe a method the teacher could use to investigate how the

frequency of the wave affects the wavelength.

[4 marks]

Use the Physics Equations Sheet to answer questions 06.2 and 06.3.

06.2 Which equation links frequency (f), wavelength (λ) and wave speed (v)?

[1 mark]

*23* Tick ( ) one box.

f = λ × v

λ = f × v

v = f × λ

06.3 The wave on the string has a frequency of 45.0 Hz.

The wave speed is 35.1 m/s.

Calculate the wavelength of the wave.

[3 marks]

Wavelength = m

Mark scheme

Show the mark scheme The mark scheme provides a level-based marking grid for the 4-mark method question (06.1), listing indicative content such as adjusting frequency, keeping masses constant, and using a metre rule. For 06.2, it identifies 'v = f × λ' as the correct equation. For 06.3, it shows a three-step calculation: substituting values into the equation (35.1 = 45.0 × λ), rearranging for λ (35.1 / 45.0), and the final answer of 0.78 m.

Question 6

AO /

Question Answers Mark

Spec. Ref.

06.1 Level 2: The method would lead to the production of a valid 3–4 AO1

outcome. The key steps are identified and logically sequenced. 6.6.1.2

RPA20

Level 1: The method would not lead to a valid outcome. Some 1–2

relevant steps are identified, but links are not made clear.

No relevant content 0

Indicative content

• use the signal generator to adjust the frequency

• keep the number of masses the same

• move the wooden bridge

• observe a steady / stationary wave pattern

• use the metre rule to measure the wavelength

• repeat using different values of frequency

• repeat for different stationary wave patterns

AO /

Question Answers Extra information Mark

Spec. Ref.

06.2 v = f × λ 1 AO1

6.6.1.2

AO /

Spec. Ref.

06.3 35.1 = 45.0 × λ 1 AO2

6.6.1.2

35.1

λ = 1

45.0

λ = 0.78 allow 0.780 1

Total Question 6 8

How to answer it

Investigating Waves on a String

What this question tests

This question assesses your knowledge of Required Practical 20. You need to demonstrate how to conduct a valid experiment, recall the wave speed equation, and perform a calculation involving rearrangement.

Part 06.1

Experimental Method

Describe a method to investigate how frequency affects wavelength.

✅ Correct Answer (Logical Steps)

  1. Use the signal generator to adjust the frequency.
  2. Move the wooden bridge until a clear, steady wave pattern (stationary wave) is seen.
  3. Use the metre rule to measure the wavelength of the wave.
  4. Repeat the process using different values of frequency.
  5. Keep the masses on the string the same (control variable).

🧠 Exam Technique

For a 4-mark "Describe a method" question, the examiner looks for a logical sequence. If your steps are jumbled or missing a key piece of equipment (like the metre rule), you will likely be capped at 2 marks.

Tip: Always mention what you are measuring, what you are changing, and what you are keeping the same!

💡 Key Knowledge: Stationary Waves

The "loops" you see on the string are called stationary waves. One full wavelength consists of two loops. If you only measure one loop, you must double it to find the wavelength (λ).

Part 06.2

The Wave Equation

Which equation links frequency (f), wavelength (λ) and wave speed (v)?

✅ Correct Choice

v = f × λ

Wave speed = frequency × wavelength

❌ Common Errors

Students often mix up the symbols. Remember:

  • v = velocity (m/s)
  • f = frequency (Hz)
  • λ = wavelength (m)
Part 06.3

Calculating Wavelength

Frequency = 45.0 Hz | Speed = 35.1 m/s. Calculate wavelength.

📐 Step-by-Step Calculation

  1. State the formula: v = f × λ
  2. Substitute the values: 35.1 = 45.0 × λ
  3. Rearrange to find λ: λ = 35.1 / 45.0
  4. Final Answer: 0.78 m

🧠 Examiner Insight

Even if you get the final answer wrong, you can get 2 marks for showing the correct substitution and rearrangement. Always write down your working!

❌ Calculation Traps

The "Big / Small" Trap: Don't just divide the bigger number by the smaller one. Always follow the algebra. If you did 45.0 / 35.1, you would lose 2 out of 3 marks.

📝 Summary for Revision

  • Independent Variable: Frequency (changed via signal generator).
  • Dependent Variable: Wavelength (measured with a ruler).
  • Control Variable: Tension in the string (kept constant by not changing the masses).
  • Relationship: As frequency increases, wavelength decreases (they are inversely proportional).

Topics

Physics · P6: Waves

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 2 (Foundation), 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.