AQA GCSE Physics Physics Paper 1 (Foundation), June 2024: Question 7
9 marks · Standard Demand difficulty · Short Answer
Identify wire insulation colours, fuse circuit symbols, calculate current and thermal energy to melt a fuse wire, and analyze energy dissipation.
Practise this questionQuestion
Question text
07 An electrical appliance is connected to the mains electricity supply using a
three-core cable.
Figure 13 shows a three-core cable.
Figure 13
07.1 What colour is the insulation covering the live wire inside the cable?
[1 mark]
Tick ( ) one box.
Blue
Brown
Green and yellow
Orange
07.2 What colour is the insulation covering the neutral wire inside the cable?
[1 mark]
Tick ( ) one box.
Blue
Brown
Green and yellow
Orange 33
The plug connected to the cable contains a fuse.
A fuse contains a wire that is designed to melt when the current is too great.
07.3 What is the circuit symbol for a fuse?
[1 mark]
Tick ( ) one box.
07.4 The wire in the fuse melts when there is a charge flow of 2.0 C in a time of 0.40 s.
Calculate the current in the wire when it melts.
Use the equation:
charge flow
current =
time
[2 marks]
34 Current = A
07.5 The mass of the wire is 0.016 g.
specific latent heat of fusion of the wire = 60 000 J/kg
Calculate the change in thermal energy needed to melt the wire.
Use the Physics Equations Sheet.
[3 marks]
Change in thermal energy = J
07.6 The fuse transfers some energy to the surroundings as it melts.
How does transferring energy to the surroundings affect the total energy needed to
melt the fuse?
[1 mark]
Tick ( ) one box.
The total energy will be smaller.
The total energy will be the same.
The total energy will be greater.
Mark scheme
Show the mark scheme
Question 7
AO /
Question Answers Extra information Mark
Spec. Ref.
07.1 brown 1 AO1
4.2.3.2
AO /
Spec. Ref.
07.2 blue 1 AO1
4.2.3.2
AO /
Spec. Ref.
07.3 1 AO1
4.2.1.1
AO /
Spec. Ref.
07.4 2.0 1 AO2
current = 4.2.1.2
0.40
current = 5.0 (A) 1
AO /
Spec. Ref.
07.5 m = 0.000016 (kg) 1 AO2
or 4.3.2.3
m = 1.6 × 10–5 (kg)
E = 0.000016 × 60 000 allow a correct substitution using 1
an incorrectly / not converted
value of m
E = 0.96 (J) allow an answer consistent with 1
an incorrectly / not converted
value of m – – –
AO /
Spec. Ref.
07.6 the total energy will be greater 1 AO3
4.1.2.1
4.3.2.3
Total Question 7 9
How to answer it
Mains Electricity, Circuit Symbols, and Latent Heat Study Guide
What this question tests
This question assesses your knowledge of domestic mains electricity (three-core cable wire colours), standard circuit symbols, charge and current calculations, specific latent heat calculations involving unit conversions (grams to kilograms), and energy conservation principles during state changes.
Live Wire Colour
✅ Correct Answer
Brown
💡 Key Knowledge
In a three-core mains cable, the live wire carries alternating potential difference from the supply. It is always covered in brown insulation for safety and identification.
Neutral Wire Colour
✅ Correct Answer
Blue
💡 Key Knowledge
The neutral wire completes the circuit by returning current from the appliance back to the mains supply. Its insulation is coloured blue. (Remember: Earth is green and yellow striped).
Circuit Symbol for a Fuse
✅ Correct Answer
The box showing a rectangle with a straight wire passing horizontally straight through the middle.
🧠 Exam Technique
Make sure you do not confuse a fuse symbol with a resistor (resistor is just a rectangle without the wire running through it) or a thermistor/LDR.
Calculating Current from Charge and Time
📐 Step-by-Step Calculation
- Identify equation: current = charge flow / time
- Substitute values: current = 2.0 / 0.40
- Calculate final answer: 5.0 A
❌ Common Errors & Examiner Insights
Students rarely stumble on this rearrangement, but always ensure your final answer includes the correct unit ( A ) and matches the significant figures given in the question data (2 sig fig).
Calculating Thermal Energy to Melt a Fuse
📐 Step-by-Step Calculation
- Convert mass to kilograms: 0.016 g = 0.016 / 1000 = 0.000016 kg (or 1.6 × 10⁻⁵ kg )
- Identify equation from Physics Equations Sheet: Energy = mass × specific latent heat ( E = m × L )
- Substitute values and calculate: E = 0.000016 × 60 000 = 0.96 J
❌ Common Errors & Mark Scheme Leniency
The Trap: Forgetting to convert grams into kilograms. Notice that the mark scheme allows ecf (error carried forward): if a student uses m = 0.016 directly without converting, they get 960 J . While this loses the conversion mark, examiners still award credit for correct substitution and arithmetic!
Energy Transfer to Surroundings
✅ Correct Answer
The total energy will be greater.
💡 Key Knowledge
To both melt the wire (change its state) and lose thermal energy to the surrounding air by heating, the total initial energy supplied must account for both outputs. Therefore, the total energy required/involved is greater than just the latent heat value alone due to thermal dissipation.
Topics
Physics · P1: Energy · P2: Electricity · P3: Particle Model of Matter
Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 1 (Foundation), June 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.