AQA GCSE Physics Physics Paper 2 (Higher), June 2024: Question 4
14 marks · Standard Demand difficulty · Short Answer
Analyze pressure in the Mariana Trench, calculate depth, identify seismic wave types and Earth layers, calculate wave wavelength, and describe the relationship between earthquake distance and wave arrival time difference.
Practise this questionQuestion
Question text
04 The Mariana Trench is the deepest part of the Pacific Ocean.
Figure 8 shows a submarine going to the bottom of the Mariana Trench.
Figure 8
04.1 The depth of the submarine increases.
Explain what happens to the pressure on the submarine.
[2 marks]
04.2 The submarine moved from the surface of the water to the bottom of the
Mariana Trench.
The change in pressure was 110 000 kPa.
mean density of sea water = 1026 kg/m3
gravitational field strength = 9.8 N/kg
Calculate the depth of the Mariana Trench.
Use the Physics Equations Sheet.
[4 marks]
Depth = m
Earthquakes often occur at the Mariana Trench.
P-waves and S-waves are produced by earthquakes.
04.3 Which statement describes P-waves and S-waves?
[1 mark]
Tick ( ) one box.
Both P-waves and S-waves are longitudinal.
Both P-waves and S-waves are transverse.
P-waves are longitudinal and S-waves are transverse.
P-waves are transverse and S-waves are longitudinal.19
04.4 Figure 9 shows the layers inside the Earth.
An earthquake occurs at the position shown.
Figure 9
Which letter shows the position where only P-waves will be detected?
Give a reason for your answer.
[2 marks]
Tick ( ) one box.
A B C D
*18* Reason
04.5 An S-wave has a frequency of 3.6 Hz.
The S-wave has a speed of 4.5 km/s.
Calculate the wavelength of this S-wave.
Use the Physics Equations Sheet.
[3 marks]
Wavelength = m
04.6 A seismometer is a device that detects earthquakes.
P-waves travel at a known speed between an earthquake and a seismometer.
S-waves travel at a slower speed than P-waves.
A P-wave and an S-wave from the earthquake arrive at the seismometer at
different times.
Describe the relationship between the distance from the earthquake to the
seismometer and the time between the P-wave and the S-wave arriving.
[2 marks]
Mark scheme
Show the mark scheme
Question 4
AO /
Question Answers Extra information Mark
Spec. Ref.
04.1 the height of the (column of) allow volume / mass for height 1 AO1
water above the submarine 4.5.5.1.2
increases
which increases the force / allow p = ρgh and ρ and g 1
weight (of the water) acting on remain constant so pressure
the submarine so pressure increases
increases
AO /
Spec. Ref.
04.2 p = 110 000 000 Pa 1 AO2
4.5.5.1.2
110 000 000 = 1026 × 9.8 × Δh allow a correct substitution of an 1
incorrectly / not converted value
for p
110 000 000 allow a correct re-arrangement 1
Δh = using an incorrectly / not
1026 × 9.8
converted value for p
Δh = 10 940 (m) allow a correct calculation from 1
using an incorrectly / not
converted value for p
allow 11 000 (m) if correct
working shown
AO /
Spec. Ref.
04.3 P-waves are longitudinal and S- 1 AO1
waves are transverse – – – 4.6.1.5
AO /
Spec. Ref.
04.4 D 1 AO3
4.6.1.5
only P-waves can travel through allow only P-waves can travel 1
liquids through the outer core
allow S waves cannot travel
through liquids
allow S waves cannot travel
through the outer core 13
MP2 dependent on MP1
AO /
Spec. Ref.
04.5 4500 = 3.6 × λ allow a correct substitution of an 1 AO2
incorrectly / not converted value 4.6.1.2
for v
4500 allow a correct re-arrangement 1
λ = using an incorrectly / not
3.6
converted value for v
λ = 1250 (m) allow 1300 (m) 1
only allow an answer consistent
with a correctly converted value
for v
AO /
Spec. Ref.
04.6 the distance is (directly) allow they are (directly) 2 AO3
proportional to the time between proportional 4.5.6.1.2
the two waves arriving (at the
seismometer)
allow a greater distance means
a greater time for 1 mark
allow there is a positive
correlation for 1 mark
Total Question 4 14
How to answer it
Pressure in Fluids and Seismic Waves Study Guide
What this question tests
This question assesses your understanding of liquid pressure calculations (p = h × ρ × g), the properties of seismic waves (P-waves and S-waves), seismic wave calculations (v = f × λ), and interpreting graphical or proportional relationships in geophysical contexts.
Submarine Depth and Pressure
✅ Correct Answer
The height of the water column above the submarine increases, which increases the force/weight of the water acting on the submarine, causing the pressure to increase.
💡 Key Knowledge
Liquid pressure depends on depth. As depth increases, the column of water above becomes taller, meaning there is more weight of water pressing down due to gravity: p = hρg .
🧠 Exam Technique
Make sure you link depth ( h ) directly to the weight or force of the fluid above. Vague answers like "there is more water" without mentioning force or height will not score both marks.
Calculating the Depth of the Mariana Trench
✅ Correct Answer
10 940 m (or 11 000 m if working shows unit conversion consideration).
📐 Step-by-Step Calculation
- Convert units: Pressure must be in Pascals (Pa). Convert 110 000 kPa to Pa by multiplying by 1,000.
Pressure ( p ) = 110 000 000 Pa . - State the formula: p = h × ρ × g (from the physics equations sheet).
- Rearrange the formula: h = p / (ρ × g)
- Substitute values: h = 110 000 000 / (1026 × 9.8)
- Evaluate: h = 110 000 000 / 10054.8 = 10940.08... m
❌ Common Errors
- Unit Trap: Forgetting to convert kiloPascals (kPa) into Pascals (Pa) is the #1 place students lose marks.
- Rounding too early: Keeping intermediate numbers in your calculator prevents rounding errors in the final answer.
Properties of P-waves and S-waves
✅ Correct Answer
Tick the box: P-waves are longitudinal and S-waves are transverse.
💡 Key Knowledge
Recall wave types:
• P-waves (Primary waves): Longitudinal seismic waves (oscillations parallel to energy transfer).
• S-waves (Secondary waves): Transverse seismic waves (oscillations perpendicular to energy transfer).
Detecting Seismic Waves through Earth Layers
✅ Correct Answer
Letter: D
Reason: Only P-waves can travel through liquids (and S-waves cannot travel through the liquid outer core).
💡 Key Knowledge
Earth's structure includes a liquid outer core. Transverse waves (S-waves) cannot travel through liquids because liquids cannot support shear stresses. Longitudinal waves (P-waves) can travel through both solids and liquids.
🧠 Exam Technique
This is a dependent two-part mark scheme (MP2 is dependent on MP1). You must correctly identify letter D and give the scientific reason involving the state of matter (liquid outer core) blocking S-waves.
Calculating S-wave Wavelength
✅ Correct Answer
1250 m (allow 1300 m if using a rounded speed value).
📐 Step-by-Step Calculation
- State the wave equation: v = f × λ (Speed = Frequency × Wavelength)
- Rearrange for wavelength ( λ ): λ = v / f
- Substitute values: λ = 4500 / 3.6
- Calculate final value: λ = 1250 m
❌ Common Errors
- Failing to rearrange the equation properly, resulting in v × f instead of v / f . Always double-check your substitution against the equation sheet.
Seismic Wave Arrival Times and Distance
✅ Correct Answer
The distance is (directly) proportional to the time between the two waves arriving at the seismometer (or a positive correlation / greater distance means greater time gap).
💡 Key Knowledge
Since P-waves travel faster than S-waves, the time gap ( t_S - t_P ) widens the further the waves travel from the earthquake epicentre. This time difference is used directly by seismologists to locate epicentres.
🧠 Exam Technique
Use precise scientific terminology. Stating that they are "directly proportional" or describing a clear positive linear trend guarantees full marks.
Topics
Physics · P5: Forces · P6: Waves
Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 2 (Higher), June 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.