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Figure 3 shows some of the apparatus that students use to determine the resistance of a piece of iron wire - Edexcel - GCSE Physics - Question 2 - 2023 - Paper 2
Question 2
Figure 3 shows some of the apparatus that students use to determine the resistance of a piece of iron wire. Add connecting wires, a voltmeter and an ammeter to comp... show full transcript
Worked Solution & Example Answer:Figure 3 shows some of the apparatus that students use to determine the resistance of a piece of iron wire - Edexcel - GCSE Physics - Question 2 - 2023 - Paper 2
Step 1
Add connecting wires, a voltmeter and an ammeter to complete the circuit in Figure 3
Answer
To complete the circuit, connect the voltmeter in parallel with the iron wire. The voltmeter will measure the voltage across the wire. Then, connect the ammeter in series with the iron wire so that it can measure the current flowing through the wire. Ensure that connecting wires are correctly placed to allow for a complete circuit.
Step 2
Figure 4 shows a graph of the results.
Answer
The graph (not provided here) displays a straight line indicating a direct proportional relationship between the resistance (in ohms) and the length of the wire (in cm). This suggests that as the length of the wire increases, the resistance also increases, which is a fundamental property of conductive materials.
Step 3
Step 4
Explain how the variable resistor affects the current in the circuit.
Answer
The variable resistor increases the resistance of the circuit. Therefore, this keeps the current flowing through the circuit constant or small. A higher resistance reduces the flow of charge, leading to a lower current. If the current increases, the temperature of the iron wire also increases, which can be critical as it may affect the wire's properties.