AQA GCSE Physics Physics Paper 1 (Foundation), June 2024: Question 11

9 marks · Standard Demand difficulty · Extended Answer

Describe a method to investigate how the length of a wire affects its resistance, identify the correct graph showing this relationship, and explain why a 1.50 V cell is not an electrical hazard.

Practise this question

Question

Question text

11 A student investigated how the length of a wire affects the resistance of the wire at

constant temperature.

Figure 18 shows the circuit used.

Figure 18

11.1 The student plotted a graph of resistance against the length of wire.

Describe a method the student could have used to collect the data needed to

plot the graph.

[6 marks]

11.2 Which graph shows the relationship between the resistance of a wire at constant

temperature and its length?

[1 mark]

Tick ( ) one box.

11.3 The student used a cell that had a potential difference of 1.50 V.

Explain why the cell was not an electrical hazard to the student in the investigation.

*45* [2 marks]

Mark scheme

Show the mark scheme

Question 11

AO /

Question Answers Mark

Spec. Ref.

11.1 Level 3: The method would lead to the production of a valid 5–6 AO1

outcome. The key steps are identified and logically sequenced. 4.2.1.3

RPA3

Level 2: The method would not necessarily lead to a valid 3–4

outcome. Most steps are identified, but the method is not fully

logically sequenced.

Level 1: The method would not lead to a valid outcome. Some 1–2

relevant steps are identified, but links are not made clear.

No relevant content 0

Indicative content

• measure the length of the wire (between the crocodile clips)

using the ruler

• length varied by moving crocodile clips

• current measured with ammeter

• potential difference measured with voltmeter

• calculate resistance for each length

• use V = IR to calculate resistance

• record current and pd for different lengths

• repeat readings of current and pd for each length and mean

values calculated

• remove any anomalous readings

• ensure values of current are low to minimise heating of wire

• ensure circuit is disconnected between readings

Level 2:

Varying the length of the wire. Measurements / equipment needed

for pd and current.

AO /

Question Answers Extra information Mark

Spec. Ref.

11.2 1 AO1

4.2.1.3

4.2.1.4

RPA3

– – –

AO /

Spec. Ref.

11.3 potential difference is (very) low 1 AO1 25

(so) no risk of electric shock allow less risk of electric shock 1 AO3

(so) no risk of electrocution 4.2.1.3

allow so wire won’t melt RPA3

allow so wire won’t get hot

Total Question 11 9

How to answer it

Investigation: Resistance and Length of a Wire

What this question tests

This set of questions assesses your knowledge of Required Practical Activity 3 (RPA3): investigating how the length of a wire affects its electrical resistance. It tests your ability to write a logical step-by-step experimental method (6-mark level of response), interpret graphical relationships, and understand safety precautions associated with low-voltage electrical circuits.

Question 1.1 — [6 Marks]

Describing the Experimental Method

💡 Key Knowledge & Method Steps

Measure the length of the wire using a metre ruler between the two crocodile clips.
Vary the length of the wire systematically (e.g., increase by 10 cm or 20 cm intervals).
Record the potential difference ( V ) from the voltmeter and the current ( I ) from the ammeter.
Calculate the resistance for each length using Ohm's Law formula: R = V / I .

🧠 Exam Technique (Level of Response)

To achieve Level 3 (5–6 marks), your method must be logical, detailed enough for someone else to replicate, and include key control or accuracy measures:

Mention repeating the readings for each length to calculate a mean.
State that the current should be kept low or the circuit switched off between readings to prevent the wire from heating up (temperature changes affect resistance!).

❌ Common Errors

Forgetting to state that resistance is calculated using R = V / I after measuring V and I .
Failing to mention temperature control (leaving the current switched on continuously causes the wire to heat up and changes its resistance).

Mark Scheme Breakdown: Level 3 (5–6 marks) requires a valid, logically sequenced method covering setup, measurements, calculation of resistance, and steps to ensure accuracy (such as taking repeats and controlling heating effects).

Question 1.2 — [1 Mark]

Identifying the Graphical Relationship

✅ Correct Answer

Tick the third graph box (the straight line going up through the origin).

💡 Key Knowledge

Resistance is directly proportional to the length of a wire. As the length increases, the resistance increases at a constant rate. This produces a straight line graph passing directly through the origin (0,0).

Mark Scheme Breakdown: 1 mark for selecting the correct straight-line graph showing direct proportionality.

Question 1.3 — [2 Marks]

Explaining Circuit Safety

✅ Correct Answer

Any two of the following points:

The potential difference is very low (1.50 V).
There is no risk of an electric shock / electrocution.
The low potential difference ensures the wire will not melt or get dangerously hot.

🧠 Exam Technique & Examiner Commentary

Students often lose the second mark by just saying "it's safe". You must link the cause (low potential difference of 1.50 V) to the effect (insufficient voltage to drive a dangerous current through a human body or cause severe heating).

Mark Scheme Breakdown: 1 mark for stating the potential difference is low, and 1 mark for linking this to a low risk of electric shock or the wire not melting/getting hot.

Topics

Physics · Required Practicals · Required Practicals · P2: Electricity

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.