AQA GCSE Physics Physics Paper 2 (Higher), June 2025: Question 1

Thunderstorms: Light vs Sound Waves & Wave Calculations

WHAT THIS QUESTION TESTS

Core Topics: Wave Properties (Transverse vs Longitudinal, Mechanical vs Electromagnetic) and Motion Calculations.

Comparing Waves: Identifying fundamental differences (nature, medium requirements, speed, wavelength) and universal similarities (wave behaviours like reflection/refraction, energy transfer).
Equation Recall: Identifying the relationship connecting speed, distance, and time.
Calculation Skills: Rearranging equations to solve for time, substituting values, and providing correct SI units.

QUESTION 01.1 • 6 MARKS

Comparing Visible Light Waves and Sound Waves

Extended Response: Describe the similarities and differences

✅ Model Answer Points

Differences:

Wave type: Visible light is a transverse wave; sound is a longitudinal wave.
Nature: Light is an electromagnetic wave; sound is a mechanical wave.
Medium requirement: Sound needs a material medium (cannot travel through a vacuum); light can travel through a vacuum.
Speed in air: Light travels much faster (3 × 10⁸ m/s) than sound (approx. 330 m/s).
Speed in solids: Sound travels faster in solids than in air; light travels slower in solids (like glass) than in air.
Frequency & Wavelength: Sound has lower frequency and longer wavelength than visible light.

Similarities:

Both transfer energy without transferring matter.
Both can undergo reflection, refraction, and diffraction.
Both obey the wave equation: v = f × λ .

🧠 Exam Technique & Level Criteria

This is a Level of Response question:

Level 2 (4–6 marks): Must give a balanced account containing both similarities and differences, clearly articulated with accurate scientific terms.
Level 1 (1–3 marks): Only gives differences OR only gives similarities, or writes brief bullet points without clear comparison.

Top-Tip: Use comparative words like "whereas", "in contrast", or "both". For example: "Light is transverse, whereas sound is longitudinal."

❌ Common Student Errors

Only listing differences: Many students forget to state similarities (e.g., both reflect and refract) and cap themselves at Level 1 (max 3 marks).
Confusing wave directions: Saying sound moves up and down while light moves back and forth (getting transverse/longitudinal oscillations reversed).
Medium confusion: Stating that light cannot travel through solids, or that sound travels fastest in a vacuum (sound cannot travel in a vacuum at all!).

💡 Key Knowledge Check

Transverse: Oscillations are perpendicular (at 90°) to the direction of energy transfer.
Longitudinal: Oscillations are parallel to the direction of energy transfer (consist of compressions and rarefactions).
Why you see lightning first: Light reaches your eyes almost instantaneously because its speed is roughly 1 million times faster than sound in air!

QUESTION 01.2 • 1 MARK

Selecting the Correct Motion Equation

Which equation links distance (s), speed (v), and time (t)?

✅ Correct Box to Tick

☑ speed = distance / time

In standard physics notation: v = s / t

❌ Incorrect Options

☒ speed = distance × time (incorrect multiplication)
☒ speed = time / distance (inverted fraction)

Check the formula sheet: This standard relation is provided on the AQA GCSE Physics equation sheet as s = v t .

QUESTION 01.3 • 3 MARKS

Calculating the Time Taken for Sound to Travel

Distance = 13 200 m, Speed of sound = 330 m/s. Calculate time taken.

📐 Step-by-Step Calculation

Step 1: Identify values and state the formula
Distance ( s ) = 13 200 m
Speed ( v ) = 330 m/s
Formula: speed = distance / time or s = v × t

Step 2: Substitute known numbers into the formula [1 Mark]
330 = 13 200 / t or 13 200 = 330 × t

Step 3: Rearrange to make time (t) the subject [1 Mark]
t = 13 200 / 330

Step 4: Calculate final answer [1 Mark]
t = 40 s

🧠 Mark Breakdown

Mark 1 (Substitution): Showing 330 = 13 200 / t or 13 200 = 330 × t . Always substitute before rearranging to secure this method mark!
Mark 2 (Rearrangement): Correct division setup t = 13 200 / 330 .
Mark 3 (Answer): Accurate value of 40 (the unit 's' is already printed on the answer line).

❌ Common Pitfalls

Multiplying instead of dividing: Calculating 13 200 × 330 = 4 356 000 . Always sanity check: sound cannot take over an hour to travel 13 km!
Dividing upside-down: Calculating 330 / 13 200 = 0.025 s . Remember that time = distance / speed.