AQA GCSE Combined Science: Trilogy Physics Paper 2 (Higher), June 2025: Question 3

12 marks · Standard Demand difficulty · Short Answer

Explain properties, hazards, wavelength calculation, wavefront refraction, and ray diagram for ultraviolet and visible light.

Practise this question

Question

$The question consists of six parts: 03.1 asks for the definition of transverse waves for 2 marks. 03.2 asks for one other health risk from ultraviolet exposure besides sunburn and eye damage for 1 mark. 03.3 is a sentence completion comparing the wavelength of ultraviolet to visible light for 1 mark. 03.4 requires calculating the wavelength in nanometres of light with frequency 6.25 × 10^14 Hz and speed 3.00 × 10^8 m/s for 4 marks. 03.5 shows a wavefront diagram (Figure 3) of visible light entering a lens from air, asking to explain why refraction occurs for 2 marks. 03.6 shows Figure 4 with a ray incident on a glass block at an angle of 45°, asking to draw the normal line and the refracted ray at an angle of refraction of 28° for 2 marks.$

Question text

03 A pair of sunglasses has lenses that absorb all ultraviolet and some visible light.

03.1 Ultraviolet and visible light are both transverse waves.

What is meant by ‘transverse waves’?

[2 marks]

03.2 Ultraviolet can cause sunburn and eye damage.

Give one other risk to health from exposure to ultraviolet.

[1 mark]

03.3 Complete the sentence.

[1 mark]

Compared with the wavelength of visible light, the wavelength of ultraviolet

is 10 .

03.4 A wave of visible light has a frequency of 6.25 × 1014 Hz.

speed of light = 3.00 × 108 m/s

Calculate the wavelength of this light.

Use the Physics Equations Sheet.

Give your answer in nanometres (nm).

[4 marks]

11 Wavelength = nm

03.5 A ray of visible light incident on the lens in a pair of sunglasses is refracted.

Figure 3 shows a wave front diagram for visible light incident on the lens.

Figure 3

For each wave front, one end of the wave front enters the lens before the other end.

Explain why the light refracts as it enters the lens.

[2 marks]

03.6 Figure 4 shows a ray of visible light incident on glass.

The angle of incidence is 45°.

Figure 4

The angle of refraction of the ray in the glass is 28°.

Complete the ray diagram in Figure 4 to show the path of the ray in the glass.

You should:

• draw the normal line

• draw the refracted ray in the glass.

You do not need to draw the ray leaving the glass.

[2 marks]

Mark scheme

Show the mark scheme

$The mark scheme details criteria for Question 3: 03.1 awards 2 marks for oscillations or vibrations being perpendicular to the direction of energy transfer or wave travel. 03.2 awards 1 mark for skin cancer or causes skin to age prematurely / skin cell mutation. 03.3 awards 1 mark for 'shorter'. 03.4 awards 4 marks: substitution into v = f lambda, rearranging lambda = 3.00 × 10^8 / 6.25 × 10^14, calculating 4.80 × 10^-7 m, and converting to 480 nm. 03.5 awards 2 marks for stating the speed of light decreases in the lens, so one end of the wavefront slows down before the other. 03.6 awards 2 marks: 1 mark for drawing the normal line at the point of incidence perpendicular to the surface, and 1 mark for drawing the refracted ray bent towards the normal at an angle of refraction of 28 degrees.$

Question 3

AO /

Question Answers Extra information Mark

Spec. Ref.

03.1 oscillations / vibrations are allow oscillations / vibrations are 2 AO1

perpendicular to the direction of perpendicular to the direction of 6.6.1.1

energy transfer wave travel

allow 1 mark for oscillations/

vibrations are perpendicular

AO /

Spec. Ref.

03.2 skin cancer allow skin cell mutation 1 AO1

or 6.6.2.3

causes skin to age ignore cancer unqualified

(prematurely)

AO /

Spec. Ref.

03.3 shorter 1 AO1

6.6.2.1

AO /

Spec. Ref.

03.4 3.00 × 108 = 6.25 × 1014 × λ 1 AO2

6.6.1.2

3.00 × 108 1

λ = 14

6.25 × 10

λ = 4.80 × 10–7 (m) 1

λ = 480 (nm) allow a correct conversion to nm 1

of their incorrectly calculated

value of λ using the numbers

– from the question TRILOGY – 8464/P/2H –

AO /

Spec. Ref.

03.5 the speed of the light / waves / allow the speed of light / waves / 1 AO1

wavefronts decreases (when wavefronts is less in the lens 6.6.2.2

entering the lens) (than in air)

ignore lens has a higher density

than air 11

ignore references to refractive

index

(so) one end of the wavefront 1

slows before the other end

AO /

Spec. Ref.

03.6 normal line drawn allow a normal line that only 1 AO2

extends from the boundary into 6.6.2.2

the glass

ray drawn with an angle of refraction of 28°

ignore ray below the glass

Total Question 3 12

How to answer it

Electromagnetic Waves, Wave Speed & Refraction

What this question tests

This 12-mark question assesses fundamental concepts across electromagnetic waves and wave properties:

Defining transverse waves in terms of oscillation and energy transfer direction.
Recalling specific biological hazards of ultraviolet (UV) radiation.
Comparing properties across the electromagnetic spectrum (wavelength and frequency).
Rearranging the wave equation ( v = f × λ ) and converting standard units to nanometres ( nm ).
Explaining wavefront refraction caused by changes in wave speed.
Accurately constructing a refraction ray diagram including normal line and angle measurement.

Question 03.1 • 2 Marks

Definition of Transverse Waves

AQA Specification 6.6.1.1

✅ Model Answer

The oscillations (or vibrations) are perpendicular (at 90°) to the direction of energy transfer (or direction of wave travel).

💡 Mark Breakdown

[1 mark]: Oscillations / vibrations are perpendicular / at right angles.
[1 mark]: ...to the direction of energy transfer / wave travel.

❌ Common Errors

Saying "the wave moves up and down" without mentioning oscillations or direction of travel.
Confusing transverse with longitudinal ("parallel instead of perpendicular").
Omitting "energy transfer" or "wave travel" entirely.

🧠 Exam Technique

Always state what is oscillating and compare its direction explicitly to the direction of wave travel / energy transfer. Never just write "moves at 90°".

Question 03.2 • 1 Mark

Health Risks of Ultraviolet Exposure

AQA Specification 6.6.2.3

✅ Acceptable Answers (Any One)

Skin cancer
Causes premature skin ageing
Skin cell mutation

❌ Common Errors & Examiner Notes

Writing just "cancer" unqualified — the mark scheme explicitly states: "ignore cancer unqualified".
Repeating "sunburn" or "eye damage" — these were already given in the question stem.

Question 03.3 • 1 Mark

Electromagnetic Spectrum Trends

AQA Specification 6.6.2.1

✅ Completed Sentence

Compared with the wavelength of visible light, the wavelength of ultraviolet is shorter.

💡 Spectral Order (Decreasing Wavelength / Increasing Frequency)

Radio → Microwave → Infrared → Visible → Ultraviolet → X-rays → Gamma rays

As frequency increases across the spectrum, wavelength decreases ( λ ∝ 1/f ).

Question 03.4 • 4 Marks

Calculation: Wave Equation and Unit Conversion

AQA Specification 6.6.1.2

📐 Step-by-Step Calculation

Step 1: State formula and substitute values [1 mark]
v = f × λ
3.00 × 10⁸ = 6.25 × 10¹⁴ × λ

Step 2: Rearrange to make wavelength (λ) the subject [1 mark]
λ = v / f = (3.00 × 10⁸) / (6.25 × 10¹⁴)

Step 3: Calculate wavelength in metres (m) [1 mark]
λ = 4.80 × 10⁻⁷ m (or 0.00000048 m )

Step 4: Convert metres to nanometres (nm) [1 mark]
Since 1 nm = 1 × 10⁻⁹ m , multiply by 10⁹ :
λ = 4.80 × 10⁻⁷ × 10⁹ = 480 nm

✅ Final Answer

Wavelength = 480 nm

❌ Calculation Traps

Inverting the division: dividing frequency by wave speed ( f / v ) instead of ( v / f ).
Powers of ten errors: dividing by 10⁹ instead of multiplying when converting metres to nanometres.
Calculator syntax errors: not using brackets around powers of ten: enter 3.00×10⁸ ÷ (6.25×10¹⁴) .

Error Carried Forward (ecf): If you calculate an incorrect wavelength in metres, you can still gain the 4th mark if you correctly multiply your value by 10⁹ to convert to nm.

Question 03.5 • 2 Marks

Explaining Refraction using Wavefronts

AQA Specification 6.6.2.2

✅ Model Answer

The speed of the light / wavefronts decreases as it enters the lens. [1 mark]
Since the ray enters at an angle, one end of the wavefront slows down before the other end, causing the wave to change direction. [1 mark]

💡 Examiner Guidance & Terminology

Accept: "speed of wave is less in the lens than in air".
Ignore references to "density of lens" or "refractive index" — explanation must explicitly link to speed change across the wavefront.

Question 03.6 • 2 Marks

Ray Diagram: Refraction into Glass

AQA Specification 6.6.2.2

✅ What Must Be Drawn

Normal Line [1 mark]: A dashed straight line drawn at right angles (90°) to the air-glass boundary at the point of incidence, extending into the glass.
Refracted Ray [1 mark]: A straight continuous line continuing from the point of incidence into the glass, bending towards the normal at an angle of refraction of 28° to the normal.

🧠 How to Draw to Exam Standards

Use a sharp pencil and a clear plastic ruler.
Use a protractor: measure 28° from the normal line inside the glass, NOT from the boundary surface.
Ensure the ray connects seamlessly to the incident ray at the interface.
You do not need to show the ray emerging out of the glass.

❌ Common Diagram Mistakes

Measuring the 28° angle from the glass boundary (surface) rather than from the normal line.
Drawing the normal line tilted instead of exactly 90° to the horizontal surface.
Bending the ray away from the normal instead of towards it (light slows down when entering a denser medium like glass, so it must bend towards the normal).

Topics

Physics · P6: Waves

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 2 (Higher), June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.