AQA GCSE Physics Physics Paper 1 (Foundation), June 2023: Question 10

14 marks · Standard Demand difficulty · Extended Answer

Explain direct potential difference, calculate charge flow and specific latent heat of fusion, and describe the changes in arrangement and movement of particles when ice melts and warms.

Practise this question

Question

Question 10 displays Figure 14 showing a parallel circuit with a 12 V battery connected across six parallel branches, each containing a resistor representing a heating element in a car windscreen. Part 10.1 asks for the meaning of 'direct potential difference' (1 mark). Part 10.2 asks to select the correct equation linking charge flow (Q), energy (E), and potential difference (V) from four multiple choice options (1 mark). Part 10.3 asks to calculate the charge flow through the 12 V battery when it transfers 5010 J of energy (3 marks). Part 10.4 gives the mass of ice melted at 0 °C as 0.015 kg from 5010 J of energy and asks for the specific latent heat of fusion of water (3 marks). Part 10.5 is an extended response asking to explain the changes in arrangement and movement of particles as ice melts and temperature increases to 5 °C (6 marks).
Question text

10 Figure 14 shows an electrical circuit used to heat the windscreen of a car.

Each resistor in the circuit represents a heating element.

Figure 14

10.1 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 10.2 and 10.3.

10.2 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 = 38

Q

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

5010 J of energy.

*37* [3 marks]

Charge flow = C

10.4 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 =39 J/kg

10.5 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 10. 10.1: polarity of the potential difference doesn't change (1 mark). 10.2: E = QV (1 mark). 10.3: substitution 5010 = Q x 12, rearrangement Q = 5010 / 12, answer Q = 417.5 C (3 marks). 10.4: substitution 5010 = 0.015 x L, rearrangement L = 5010 / 0.015, answer L = 334 000 J/kg (3 marks). 10.5: 3-level response matrix (5-6, 3-4, 1-2 marks) with indicative points covering regular pattern of solid to random arrangement of liquid, vibrating about fixed positions to moving freely, constant temperature during phase change due to increased potential energy, and faster movement / increased kinetic energy as water warms.

Question 10

AO /

Question Answers Extra information Mark

Spec. Ref.

10.1 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.

10.2 E = QV 1 AO1

4.2.4.2

AO /

Spec. Ref.

10.3 5010 = Q × 12 1 AO2

4.2.4.2

5010

Q = 1

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

AO /

Spec. Ref.

10.4 5010 = 0.015 × L 1 AO2

4.3.2.3

5010

L = 1

0.015

L = 334 000 (J/kg) – HYSICS – 1 –

AO /

Question Answers Mark

Spec. Ref.

10.5 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

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 10 14

How to answer it

Car Windscreen Heating & Particle Theory

📋 WHAT THIS QUESTION TESTS

This question covers core components of AQA GCSE Physics Paper 1 (Topics: Electricity & Particle Model of Matter):

  • Defining direct potential difference (d.c. characteristics).
  • Recalling and rearranging the equation relating charge, energy, and potential difference ( E = Q × V ).
  • Applying the specific latent heat of fusion equation ( E = m × L ).
  • Describing changes in particle arrangement, movement, and internal energy during a change of state and temperature rise (6-mark extended writing).
PART 10.1 • 1 MARK

Direct Potential Difference

Definition of direct potential difference (d.c.)

✅ Correct Answer

The polarity (or direction) of the potential difference does not change.

💡 Key Knowledge

  • Direct current/voltage (d.c.): Current flows in only one direction because the polarity remains fixed.
  • Alternating current/voltage (a.c.): Polarity alternates continuously (e.g., UK mains electricity).

❌ Common Errors

Stating that the potential difference "stays at a constant value" or "doesn't drop". Direct voltage can vary in magnitude (e.g., rectified a.c.), but its polarity/direction never reverses.

Mark Scheme: 1 mark for stating that the polarity (or direction) of the potential difference doesn't change.
PART 10.2 • 1 MARK

Equation: Charge, Energy, & Potential Difference

Recalling the formula from the equation sheet

✅ Correct Box to Tick

E = QV

🧠 Exam Technique

Always cross-check with the Physics Equation Sheet if provided. Remember definitions: Potential difference (V) is energy transferred (E) per unit charge (Q), which means V = E / Q . Multiplying both sides by Q gives E = QV .

Mark Scheme: 1 mark for selecting E = QV .
PART 10.3 • 3 MARKS

Calculating Charge Flow

Calculating charge flow through the battery transferring 5010 J at 12 V

📐 Step-by-Step Calculation

  1. Substitute values into equation:
    5010 = Q × 12
  2. Rearrange for charge (Q):
    Q = 5010 / 12
  3. Calculate the final answer:
    Q = 417.5 C (or 418 C )

❌ Common Errors

  • Multiplying 5010 × 12 instead of dividing.
  • Forgetting to substitute before rearranging (substituting first guarantees 1 mark even if algebraic rearrangement goes wrong).
Mark Breakdown:
[1 mark] Correct substitution: 5010 = Q × 12
[1 mark] Correct rearrangement: Q = 5010 / 12
[1 mark] Correct final answer: 417.5 (allow 418)
PART 10.4 • 3 MARKS

Specific Latent Heat of Fusion

Calculating specific latent heat ( L ) using mass and energy

📐 Step-by-Step Calculation

Equation: E = m × L

  1. Substitute given values:
    5010 = 0.015 × L
  2. Rearrange to solve for L:
    L = 5010 / 0.015
  3. Calculate value:
    L = 334 000 J/kg

🧠 Exam Technique

  • Mass is already in kilograms ( 0.015 kg ) – no conversion needed!
  • Be careful when dividing by decimals: 5010 / 0.015 makes a large number. Don't second-guess yourself; latent heat values are typically in the hundreds of thousands of J/kg.
Mark Breakdown:
[1 mark] Substitution: 5010 = 0.015 × L
[1 mark] Rearrangement: L = 5010 / 0.015
[1 mark] Correct answer: 334 000 (J/kg)
PART 10.5 • 6 MARKS

Extended Response: Particle Model & Heating

Explain changes in arrangement and movement of particles from ice at 0 °C to water at 5 °C

💡 Key Knowledge: Two Separate Stages

To score top marks, you must split your answer into the two distinct physical processes taking place:

  1. Phase Change (Melting at 0 °C): State changes from solid to liquid. Temperature remains constant. Internal energy increases because potential energy increases (bonds broken).
  2. Heating (0 °C to 5 °C): Liquid warms up. Temperature rises. Internal energy increases because kinetic energy increases (particles move faster).

✅ Model 6-Mark Answer Structure

  • Solid Ice: Particles are arranged in a regular pattern / fixed lattice and only vibrate about fixed positions.
  • During Melting (at 0 °C):
    • Temperature remains constant while melting.
    • Energy transferred increases the potential energy of particles, breaking intermolecular bonds.
  • Liquid Water: Particles are arranged in a random arrangement and are free to move past one another.
  • Warming from 0 °C to 5 °C:
    • Energy transferred increases the kinetic energy of particles.
    • Particles move faster.

🧠 Level Descriptors & Examiner Advice

Level 3 (5–6 marks): Relevant points regarding arrangement, movement, AND energy/temperature are logically linked to create a clear account of both melting and warming.

Level 2 (3–4 marks): Describes arrangement and movement well, but links to temperature or energy changes are incomplete or unclear.

Mark Scheme Exclusion: Do not spend time writing about the density of ice vs water or particle spacing. Focus strictly on arrangement and movement.
Indicative Points Required for Top Marks: Solid = regular + vibrating • Liquid = random + moving freely • Constant temperature during melt because potential energy increases • Water warms: kinetic energy increases, particles move faster.

Topics

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

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