AQA GCSE Combined Science: Trilogy Physics Paper 2 (Foundation), 2024: Question 3

9 marks · Standard Demand difficulty · Short Answer

Analyze sound wave properties, typical speed in air, and perform calculations to determine the period from frequency.

Practise this question

Question

The image shows a multi-part physics exam question about sound waves produced by an electronic whistle. It includes a photograph of the whistle, a multiple-choice question about what waves transfer (energy, mass, or temperature), and a question asking for the typical speed of sound in air. A diagram compares two sound waves, A and B, on a grid; Wave A has more cycles than Wave B in the same horizontal distance, but both reach the same vertical height. Further questions ask to identify similarities and differences between the waves, convert 4.0 kHz to Hz, and calculate the period of wave A using the formula period equals one divided by frequency. The final part asks to identify the two types of areas created by longitudinal sound waves in air from a list of terms.
Question text

03 Figure 6 shows an electronic whistle used by a referee in a football match.

Figure 6

When the button is pressed the whistle emits sound waves that travel through the air.

03.1 What is transferred by the sound waves as they travel through the air?

[1 mark]

Tick ( ) one box.

Energy

Mass

Temperature 12

03.2 What is a typical value for the speed of sound in air?

[1 mark]

Tick ( ) one box.

33 m/s

330 m/s

3300 m/s

33 000 m/s 13

The whistle can emit two different sound waves, A and B.

Figure 7 shows the two different sound waves as displayed on a screen.

The sound waves are drawn to the same scale.

Figure 7

03.3 Complete the sentences to describe a difference and a similarity between the

two waves.

Choose answers from the box.

[2 marks]

amplitude frequency wavelength period

Difference

Wave A has a greater than wave B.

Similarity

Wave A has the same as wave B.

03.4 Wave A has a frequency of 4.0 kHz.

Which of the following is the same as 4.0 kHz?

[1 mark]

Tick ( ) one box.

4.0 Hz

4000 Hz

4 000 000 Hz

4 000 000 000 Hz

03.5 Calculate the period of wave A.

Use your answer from Question 03.4 and the equation:

period =

frequency

[2 marks]

15 Period = s

03.6 Sound waves in air are longitudinal waves.

Complete the sentence to describe a sound wave.

Choose answers from the box.

[2 marks]

compression deflection diffraction rarefaction reflection

When sound waves travel through air they create areas

of and .

Mark scheme

Show the mark scheme The mark scheme table for Question 3 provides the following answers: 03.1 is 'energy' (1 mark); 03.2 is '330 m/s' (1 mark); 03.3 identifies 'frequency' as the difference and 'amplitude' as the similarity (2 marks); 03.4 is '4000 Hz' (1 mark); 03.5 shows the calculation T = 1 / 4000 resulting in 0.00025 s (2 marks); 03.6 identifies 'compression' and 'rarefaction' as the areas created (2 marks). It lists a total of 9 marks and includes specification references for each part.

Question 3

AO /

Question Answers Extra information Mark

Spec. Ref.

03.1 energy 1 AO1

6.6.1.1

AO /

Spec. Ref.

03.2 330 m/s 1 AO1

6.5.4.1.2

AO /

Spec. Ref.

03.3 frequency 1 AO1

6.6.1.2

amplitude 1

AO /

Spec. Ref.

03.4 4000 Hz 1 AO1

6.6.1.2

AO /

Spec. Ref.

03.5 allow ecf from question 03.4 AO1

6.6.1.2

T = 1

4000

0.00025 (s) 1

– – –

AO /

Spec. Ref.

either order

03.6 AO1

compression 1 6.6.1.1

rarefaction 1 11

Total Question 3 9

How to answer it

Sound Waves and Wave Properties

What this question tests

This question assesses your fundamental understanding of wave properties. You need to recall the definition of a wave, identify typical values for the speed of sound, interpret wave diagrams (oscilloscope traces), perform unit conversions (kHz to Hz), and use the wave period formula.

Parts 03.1 & 03.2

Wave Basics and Speed

Correct Answers

  • 03.1: Energy
  • 03.2: 330 m/s

Key Knowledge

Waves are oscillations that transfer energy and information without transferring matter.

The speed of sound in air is roughly 330–340 m/s. You are expected to memorize this value for the exam.

Part 03.3

Interpreting Wave Diagrams

Comparing Wave A and Wave B

Correct Answers

  • Difference: Wave A has a greater frequency than Wave B.
  • Similarity: Wave A has the same amplitude as Wave B.

Exam Technique

Look at the grid lines in Figure 7:

  • Frequency: Count how many waves fit in the box. Wave A has 4 full cycles; Wave B has only 2. More cycles = higher frequency.
  • Amplitude: Look at the height from the center line to the peak. Both waves are exactly 2 squares high.
Part 03.4

Unit Conversions

Correct Answer

4000 Hz

Prefixes to Remember

In Physics, the prefix k (kilo) always means 1000.

  • 1 kHz = 1000 Hz
  • 4.0 kHz = 4.0 × 1000 = 4000 Hz

Common Error

Students often confuse kilo (10^3) with mega (10^6). 4,000,000 Hz would be 4 MHz, not 4 kHz!

Part 03.5

Calculating the Period

Step-by-Step Calculation

  1. Identify the formula: period = 1 / frequency
  2. Use the correct units: Use the value in Hz (4000) from the previous question, not kHz.
  3. Substitute: period = 1 / 4000
  4. Calculate: 0.00025 s

Examiner Insight: ECF

This question allows ECF (Error Carried Forward). If you got 03.4 wrong but used that wrong number correctly in this formula, you could still earn 1 mark for the calculation step.

Final Answer

0.00025 s

1 mark for substitution, 1 mark for correct answer.
Part 03.6

Longitudinal Wave Structure

Correct Answers

Areas of compression and rarefaction.

Key Definitions

  • Compression: Regions where the air particles are squashed together (high pressure).
  • Rarefaction: Regions where the air particles are spread apart (low pressure).

Visualizing the Answer

If asked to draw this, you would draw a series of vertical lines. Where the lines are very close together, label it compression. Where they are far apart, label it rarefaction.

Topics

Physics · P6: Waves · P5: Forces

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.