AQA GCSE Physics Physics Paper 1 (Higher), June 2023: Question 3

14 marks · Standard Demand difficulty · Extended Answer

Recall the meaning of direct potential difference, apply energy and charge equations to a car windscreen heater, calculate specific latent heat of fusion, and explain particle arrangement and movement during melting and heating.

Practise this question

Question

Question 3 displays Figure 4, showing a circuit with a 12 V battery connected in parallel to six identical resistors representing windscreen heating elements. Part 03.1 asks what is meant by 'direct potential difference' (1 mark). Part 03.2 offers four tick-box equations relating charge flow Q, energy E, and potential difference V: E = V/Q, E = QV, E = Q/V, and E = V^2/Q (1 mark). Part 03.3 asks to calculate charge flow through the battery when it transfers 5010 J of energy (3 marks). Part 03.4 asks for the specific latent heat of fusion of water given that 5010 J melts 0.015 kg of ice at 0 °C (3 marks). Part 03.5 asks for a 6-mark explanation of the changes in arrangement and movement of the particles as the ice melts and warms to 5 °C.
Question text

03 Figure 4 shows an electrical circuit used to heat the windscreen of a car.

Each resistor in the circuit represents a heating element.

Figure 4

03.1 The 12 V battery supplies direct potential difference.

What is meant by ‘direct potential difference’?

[1 mark]

Use the Physics Equations Sheet to answer questions 03.2 and 03.3.

03.2 Which equation links charge flow (Q), energy (E) and potential difference (V)?

[1 mark]

Tick ( ) one box.

V

E =

Q

E = QV

Q

E =

V

V2

E = 8

Q

03.3 Calculate the charge flow through the 12 V battery when the battery transfers

5010 J of energy.

*07* [3 marks]

Charge flow = C

03.4 Ice forms on the windscreen at a temperature of 0 °C.

The electrical circuit transfers 5010 J of energy to the ice.

A mass of 0.015 kg of ice melts.

Calculate the specific latent heat of fusion of water.

Use the Physics Equations Sheet.

[3 marks]

Specific latent heat of fusion of water =9 J/kg

03.5 The electrical circuit was left switched on while the ice changed from a solid to a liquid

and increased in temperature to 5 °C.

Explain the changes in the arrangement and movement of the particles as the ice

melted and the temperature increased to 5 °C.

[6 marks]

Mark scheme

Show the mark scheme Mark scheme for Question 3 gives: 03.1: polarity of the potential difference doesn't change / direction doesn't change (1 mark). 03.2: E = QV (1 mark). 03.3: substitution 5010 = Q × 12, rearrangement Q = 5010 / 12, answer 417.5 C or 418 C (3 marks). 03.4: substitution 5010 = 0.015 × L, rearrangement L = 5010 / 0.015, answer 334 000 J/kg (3 marks). 03.5: 6-mark level of response rubric covering solid vs liquid arrangement (regular to random), movement (vibrating to moving freely), constant temperature during melting due to increasing potential energy, and particle speed increasing with temperature due to increasing kinetic energy. Total 14 marks.

Question 3

AO /

Question Answers Extra information Mark

Spec. Ref.

03.1 polarity of the potential allow direction of the potential 1 AO1

difference doesn’t change difference doesn’t change 4.2.3.1

AO /

Spec. Ref.

03.2 E = QV 1 AO1

4.2.4.2

AO /

Spec. Ref.

03.3 5010 = Q × 12 1 AO2

4.2.4.2

5010

Q = 1

Q = 417.5 (C) allow 418 (C) 1

AO /

Spec. Ref.

03.4 5010 = 0.015 × L 1 AO2

4.3.2.3

5010

L = 1

0.015

L = 334 000 (J/kg) 1

– HYSICS – –

AO /

Question Answers Mark

Spec. Ref.

03.5 Level 3: Relevant points (reasons / causes) are identified, given in 5–6 AO1

detail and logically linked to form a clear account. 4.3.1.1

4.3.2.1

Level 2: Relevant points (reasons / causes) are identified, and 3–4

there are attempts at logical linking. The resulting account is not

fully clear.

Level 1: Points are identified and stated simply, but their relevance 1–2

10 is not clear and there is no attempt at logical linking.

No relevant content 0

Indicative content

• particles in a solid are in a regular pattern

• particles in a liquid are in a random arrangement

• particles in a solid are vibrating about fixed positions

• particles in a liquid are moving freely

• as the ice changes to water the temperature remains constant

• because as the ice changes to water the potential energy of the

particles increases

• as the water warms the particles move faster

• so the kinetic energy of the particles increases

• internal energy is the total kinetic and potential energy of all the

particles

ignore any references to density of ice vs liquid water

ignore any references to spacing of particles

Total Question 3 14

How to answer it

Windscreen Heating Circuits & Particle Changes

📋 What this question tests

This question assesses understanding of Electricity and the Particle Model of Matter:

  • Recall of the definition of direct potential difference (d.c.).
  • Selection and rearrangement of the equation linking energy, charge flow, and potential difference ( E = Q × V ).
  • Calculating specific latent heat of fusion using E = m × L .
  • Writing an extended 6-mark explanation describing changes in particle arrangement, motion, and internal energy during melting and temperature rise.

Part 03.1: Defining Direct Potential Difference

1 Mark • AO1 Recall

✅ Correct Answer

Any one of the following:

  • The polarity of the potential difference doesn't change.
  • The direction of the potential difference doesn't change.

💡 Key Knowledge

Direct current (d.c.) is supplied by cells and batteries. Unlike alternating potential difference (a.c.) from mains electricity—which constantly reverses direction—direct potential difference maintains a fixed positive and negative terminal.

❌ Common Errors

Avoid saying "the voltage stays at 12 V" or "the voltage is constant". Direct p.d. can change in magnitude (size); what defines it as 'direct' is that its polarity/direction does not reverse.

Award 1 mark for stating that the polarity or direction does not change.

Part 03.2: Equation Linking Energy, Charge, and p.d.

1 Mark • AO1 Recall

✅ Correct Answer

Tick the second box:

E = QV

🧠 Exam Technique

Check the formula sheet provided in the exam. Look under the Electricity section for energy transferred by electrical work: energy = charge flow × potential difference .

Award 1 mark for ticking only the box next to E = QV .

Part 03.3: Charge Flow Calculation

3 Marks • AO2 Application

📐 Step-by-Step Calculation

  1. Identify values:
    E = 5010 J , V = 12 V , Q = ?
  2. Substitute into formula:
    5010 = Q × 12 [1 mark]
  3. Rearrange to solve for Q:
    Q = 5010 / 12 [1 mark]
  4. Calculate final value:
    Q = 417.5 C (or rounded to 418 C ) [1 mark]

❌ Calculation Traps

  • Inverting the division: Doing 12 / 5010 instead of 5010 / 12 .
  • Multiplying instead of dividing: Calculating 5010 × 12 . Always write the substitution step first to secure method marks even if your rearrangement goes wrong!
Mark breakdown: [1] substitution, [1] rearrangement, [1] correct answer (417.5 or 418). Unit is already given (C).

Part 03.4: Specific Latent Heat of Fusion Calculation

3 Marks • AO2 Application

📐 Step-by-Step Calculation

  1. Select the correct formula:
    Energy for a change of state = mass × specific latent heat ( E = m × L )
  2. Substitute known values:
    5010 = 0.015 × L [1 mark]
  3. Rearrange to find L:
    L = 5010 / 0.015 [1 mark]
  4. Calculate:
    L = 334 000 J/kg (or 3.34 × 10⁵ J/kg ) [1 mark]

💡 Latent Heat vs. Specific Heat Capacity

Notice the temperature stayed at 0 °C while melting. Whenever a substance changes state at a constant temperature, use Latent Heat ( E = mL ), NOT specific heat capacity ( E = mcΔθ ).

Mark breakdown: [1] correct substitution of 5010 and 0.015, [1] rearrangement, [1] correct value (334 000).

Part 03.5: Extended Response - Particle Model

6 Marks • AO1 Recall & Structured Explanation

🧠 How to Structure a Level 3 (5–6 Marks) Answer

Divide your answer into two distinct stages: Stage 1 (Melting at 0 °C) and Stage 2 (Warming from 0 °C to 5 °C). For full marks, you must discuss both particle arrangement and particle movement, and link them to energy changes.

✅ Model Answer Structure

Stage 1: Melting (Ice → Water at 0 °C)

  • Arrangement: In solid ice, particles are arranged in a regular pattern (lattice). When melted to liquid, particles become arranged in a random arrangement.
  • Movement: In solid ice, particles only vibrate about fixed positions. In liquid water, particles can move freely past one another.
  • Energy: Temperature remains constant during melting because energy supplied increases the potential energy of the particles to break intermolecular bonds, not their kinetic energy.

Stage 2: Warming (Water at 0 °C → 5 °C)

  • Movement & Energy: As temperature increases to 5 °C, the particles move faster, meaning their kinetic energy increases.
  • Internal energy: The total internal energy increases (the sum of kinetic and potential energies).

💡 Examiner Notes & Terminology

  • Do NOT confuse temperature with state change: Temperature does not rise during a change of state.
  • Ignored points: Do not waste time discussing density differences between ice and water, or the microscopic spacing between particles. The question asks specifically for arrangement and movement.

❌ Common Student Pitfalls

  • Saying particles in a solid "don't move at all" (they vibrate!).
  • Failing to mention the temperature rise from 0 °C to 5 °C (only describing melting restricts you to Level 1 or 2).
  • Confusing kinetic energy (related to temperature/speed) with potential energy (related to bonds/state).
Levels of response marking:
• Level 3 (5–6 marks): Both arrangement and movement clearly addressed for both melting and warming, logically linked with internal energy changes.
• Level 2 (3–4 marks): Relevant points identified for arrangement and movement, but links to heating/state change are incomplete.
• Level 1 (1–2 marks): Isolated factual statements about solids and liquids without clear explanation of the process.

Topics

Physics · P2: Electricity · P3: Particle Model of Matter

Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 1 (Higher), June 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.