AQA GCSE Physics Physics Paper 1 (Higher), June 2024: Question 10
12 marks · Standard Demand difficulty · Short Answer
Calculate current, mass, and discuss the effect of energy transfer on the melting time of a fuse wire in a domestic circuit.
Practise this questionQuestion
Question text
10 The live wire in a three-core cable is connected to a fuse inside a plug.
A fuse contains a wire that is designed to melt when the current gets too great.
Figure 17 shows a fuse.
Figure 17
10.1 What colour is the insulation covering the live wire in a three-core cable?
[1 mark]
10.2 Draw the circuit symbol for a fuse in the box below.
[1 mark]
10.3 The fuse wire melts when there is a charge flow of 2.0 C for 400 ms.
Calculate the current in the fuse wire.
Use the Physics Equations Sheet.
[4 marks]
Current = A
10.4 When the fuse wire is at its melting point, the additional energy needed to melt the
wire is 1.02 J.
specific latent heat of fuse wire = 60 kJ/kg
Calculate the mass of the fuse wire.
Use the Physics Equations Sheet.
[4 marks]
Mass = kg
10.5 The calculation in Question 10.4 assumes there is no energy transferred to
the surroundings.
How would the time taken for the wire to melt be affected if some energy was
transferred to the surroundings?
Give a reason for your answer.
[2 marks]
Tick ( ) one box.
Time taken would decrease
Time taken would stay the same
Time taken would increase
Reason
Mark scheme
Show the mark scheme
Question 10
AO /
Question Answers Extra information Mark
Spec. Ref.
10.1 brown 1 AO1
4.2.3.2
AO /
Spec. Ref.
10.2 1 AO1
4.2.1.1
AO /
Spec. Ref.
10.3 t = 0.400 (s) 1 AO2
4.2.1.2
2.0 = I × 0.400 allow a correct substitution of an 1
incorrectly / not converted value
of t
2.0 allow a correct rearrangement 1
I = using an incorrectly / not
0.400
converted value of t
I = 5.0 (A) allow an answer consistent with 1
an incorrectly / not converted
value of t
– – –
AO /
Spec. Ref.
10.4 L = 60 000 (J/kg) allow full credit for a correct 1 AO2
method using E = 0.00102 (kJ) 4.3.2.3
1.02 = m × 60 000 allow a correct substitution of an 1
incorrectly / not converted value
of L
1.02 allow a correct rearrangement 1
m = using an incorrectly / not
60 000
converted value of L
m = 1.7 × 10–5 (kg) allow an answer consistent with 1
an incorrectly / not converted
value of L
AO /
Spec. Ref.
10.5 time taken would increase 1 AO3
more energy would need to be MP2 dependent on scoring MP1 1 AO1
transferred (in total)
4.1.2.1
4.3.2.3
Total Question 10 12
How to answer it
Mains Electricity, Fuses, and Specific Latent Heat Study Guide
This question assesses your recall of plug wiring colours, circuit symbols, and your ability to apply core physics equations linking charge flow, current, time, and specific latent heat. It tests unit conversions (milliseconds to seconds, kilojoules to joules) and logical reasoning regarding energy transfers.
Part 10.1: Live Wire Colour
✅ Correct Answer
brown
💡 Key Knowledge
- Three-core cables have fixed insulation colours in the UK:
- Live: Brown
- Neutral: Blue
- Earth: Green and yellow stripes
Part 10.2: Circuit Symbol for a Fuse
✅ Correct Answer
A rectangle drawn inside a wire, with the straight line running completely horizontally through the middle of the box.
🧠 Exam Technique
Make sure the line goes straight through the center of the rectangle without stopping. A resistor looks similar, but a fuse specifically has the wire passing straight through it.
Part 10.3: Calculating Current
📐 Step-by-Step Calculation
- Convert units: Time must be in seconds. Convert 400 ms to seconds by dividing by 1000.
t = 400 / 1000 = 0.400 s - Recall equation: Q = I × t (Charge = Current × Time)
- Rearrange: I = Q / t
- Substitute values: I = 2.0 / 0.400
- Calculate final answer: I = 5.0 A
❌ Common Errors & Examiner Traps
- Unit slip: Forgetting to convert milliseconds (ms) into seconds (s). If you use 400 instead of 0.4 , you will get an incorrect answer of 0.005 A . Examiners do allow ecf (error carried forward) if your substitution is consistent with your incorrect unit conversion.
Part 10.4: Calculating Mass using Specific Latent Heat
📐 Step-by-Step Calculation
- Convert units: Specific latent heat must be in J/kg. Convert 60 kJ/kg by multiplying by 1000.
L = 60,000 J/kg - Recall equation: E = m × L (Energy = Mass × Specific Latent Heat)
- Rearrange: m = E / L
- Substitute values: m = 1.02 / 60,000
- Calculate final answer: m = 1.7 × 10⁻⁵ kg (or 0.000017 kg )
❌ Common Errors & Examiner Traps
- Prefix trap: Mixing up kilojoules ( kJ ) and joules ( J ). You must convert 60 kJ/kg to 60,000 J/kg before calculating.
- Rearrangement errors: Dividing latent heat by energy instead of energy by latent heat ( L / E instead of E / L ).
Part 10.5: Energy Transfer to Surroundings
✅ Correct Answer
Tick: Time taken would increase
Reason: More energy would need to be transferred (in total) to reach the melting point because some energy is lost to the surroundings.
💡 Key Knowledge & Examiner Insight
Top-level responses clearly linked the loss of thermal energy to the surroundings with the requirement for a larger total input of energy from the electrical current. Since power input remains steady, supplying more total energy takes more time.
Topics
Physics · P2: Electricity · P3: Particle Model of Matter
Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 1 (Higher), June 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.