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 so that the students can determine the resistance of the piece of iron wire.
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Answer
To complete the circuit in Figure 3, you need to:
Draw a line connecting the two connectors on either side of the iron wire to represent connecting wires.
Connect a voltmeter in parallel with the iron wire. This allows the voltmeter to measure the potential difference across the wire.
Connect an ammeter in series with the circuit. This will measure the current flowing through the iron wire.
Ensure the variable resistor is positioned in such a way that it can adjust the current flowing in the circuit.
Step 2
Figure 4 shows a graph of the results.
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Answer
Based on Figure 4, I will make the following observations based on the plotted data:
The graph indicates a linear relationship between the length of the iron wire and its resistance.
The data points suggest a straight line can effectively represent the relationship within the shaded area as guided by the marking scheme.
Step 3
Any number between 2.7 and 3.3 inclusive.
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Answer
From the graph in Figure 4, the resistance of the iron wire can be read as approximately 3.0 Ω, which falls within the required range of 2.7 Ω to 3.3 Ω.
Step 4
Explanation linking any two.
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Answer
The variable resistor is used to adjust the resistance in the circuit, which in turn controls the current. By keeping the current small or constant, we ensure that the temperature of the iron wire does not increase excessively, allowing for accurate measurement of resistance without overheating.