AQA GCSE Combined Science: Trilogy Physics Paper 2 (Foundation), 2023: Question 4

9 marks · Standard Demand difficulty · Short Answer

Identify properties of longitudinal waves, interpret wave diagrams, read a speed-temperature graph, and perform a distance calculation.

Practise this question

Question

A series of physics exam questions about sound waves. Figure 9 depicts a longitudinal wave as a series of dots with varying density, requiring labels for compression and rarefaction. Figure 11 compares two wave oscillations at 80m and 200m distances, showing a decrease in amplitude while frequency remains constant. Figure 12 is a line graph showing the speed of sound in m/s increasing linearly with temperature in degrees Celsius from 0 to 40 degrees.
Question text

04 Sound waves are longitudinal waves.

04.1 Figure 9 shows a sound wave.

Figure 9

Complete the labels on Figure 9.

Choose answers from the box.

[2 marks]

compression extension rarefaction

reflection 19 resistance

04.2 Which of the following is true for longitudinal waves?

[1 mark]

Tick ( ) one box.

Longitudinal waves transfer charge.

Longitudinal waves transfer energy.

Longitudinal waves transfer matter.20

Figure 10 shows a device a farmer uses to scare away birds.

Figure 10

The device emits a very loud sound.

The farmer measures the sound emitted by the device at different distances from21

the device.

04.3 Figure 11 shows a visual display of the sound waves at different distances from

the device.

Both waves are drawn to the same scale.

Figure 11

Which property of the wave changes between 80 m and 200 m?

[1 mark]

Tick ( ) one box.

Amplitude

Frequency

Period

Wavelength 22

Figure 12 shows how the speed of the sound emitted by the device is affected by the

temperature of the air.

Figure 12

04.4 The farmer tests the device on a day when the temperature of the air is 15 °C.

What is the speed of the sound emitted by the device when the temperature of the

air is 15 °C?

[1 mark]

23 Speed = m/s

04.5 The farmer stands a safe distance from the device.

It takes a time of 0.20 s for the sound to travel from the device to the farmer.

Calculate the distance between the device and the farmer.

Use your answer to Question 04.4 and the equation:

distance = speed × time

[2 marks]

Distance = m

04.6 Explain how the time taken for the sound to reach the farmer is affected by the

temperature of the air.

Use Figure 12.

[2 marks]

Mark scheme

Show the mark scheme The mark scheme for question 4 lists the following: 04.1 requires 'compression' and 'rarefaction' in that order; 04.2 identifies that longitudinal waves transfer energy; 04.3 identifies 'amplitude' as the changing property; 04.4 gives 340 m/s as the speed from the graph; 04.5 shows the calculation 340 multiplied by 0.20 equals 68m; 04.6 explains that higher temperature leads to greater speed and therefore the time taken is less.

Question 4

AO /

Question Answers Extra information Mark

Spec. Ref.

04.1 compression this order only 1 AO1

6.6.1.1

rarefaction 1

AO /

Spec. Ref.

04.2 longitudinal waves transfer 1 AO1

energy 6.6.1.1

AO /

Spec. Ref.

04.3 amplitude 1 AO2

6.6.1.2

AO /

Spec. Ref.

04.4 340 (m/s) allow answers in the range 339 1 AO2

to 340 (m/s) 6.6.1.2

AO /

Spec. Ref.

04.5 s = 340 × 0.20 1 AO2

6.6.1.2

s = 68 m 1

allow ecf from question 04.4

AO /

Spec. Ref.

04.6 the higher the temperature the do not accept the greater the 1 AO3

greater the speed speed the higher the 6.6.1.2

temperature

(so) time taken is less 1

Total Question 4 9

How to answer it

Properties and Speed of Sound Waves

What this question tests

This question assesses your understanding of longitudinal waves (specifically sound), identifying wave features from diagrams, interpreting graphs of speed vs. temperature, and performing basic speed-distance-time calculations.

Part 04.1

Labeling a Sound Wave

Correct Answers

  • First label: compression
  • Second label: rarefaction

Key Knowledge

In a longitudinal wave, the particles oscillate back and forth in the same direction as the wave travels.

  • Compression: Regions where particles are bunched together (high pressure).
  • Rarefaction: Regions where particles are spread apart (low pressure).
Part 04.2

Wave Fundamentals

Correct Answer

Longitudinal waves transfer energy.

Exam Technique

Remember the golden rule of waves: Waves transfer energy and information without transferring matter. If you see "transfer matter" as an option, it is almost always a distractor!

Part 04.3

Changing Wave Properties

Correct Answer

Amplitude

Visual Analysis

Look at Figure 11. The waves at 200m are "shorter" in height than the waves at 80m. The distance from the middle line to the peak is the amplitude. Since the sound gets quieter as it travels further, the amplitude decreases.

Common Error

Students often confuse amplitude (loudness) with frequency (pitch). The number of waves per cm in the diagram hasn't changed, so the frequency and wavelength remain the same.

Part 04.4

Reading the Graph

Correct Answer

340 m/s

How to read Figure 12

  1. Find 15 °C on the horizontal (x) axis.
  2. Move vertically up to the line.
  3. Move horizontally to the left to read the speed on the vertical (y) axis.
  4. The mark scheme allows a small range (339 to 340 m/s), but 340 is the exact value.
Part 04.5

Distance Calculation

Step-by-Step Calculation

  1. Identify the values: Speed = 340 m/s (from 04.4), Time = 0.20 s.
  2. Use the formula: distance = speed × time
  3. Substitute: distance = 340 × 0.20
  4. Final Answer: 68 m

Examiner Tip: ECF

This question uses ECF (Error Carried Forward). If you got the wrong speed in 04.4 but multiplied it correctly by 0.20 here, you would still get the marks for the calculation.

Part 04.6

Temperature and Time

Correct Answer

  • The higher the temperature, the greater the speed (of sound). [1 mark]
  • So the time taken is less. [1 mark]

Linking Concepts

To get full marks, you must link the cause (temperature change) to the effect (speed change) and then to the result (time taken). Use the phrase "the higher the... the greater the..." to show a clear relationship.

Common Pitfall

Do not reverse the logic. Saying "the greater the speed, the higher the temperature" is incorrect in this context because temperature is the independent variable (the thing that changes first).

Topics

Physics · P6: Waves

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 2 (Foundation), 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.