GCSE Standard Questions: Electric Circuits
Q12. Barry and Cisco investigate the resistance of a wire. They tape a length of wire to a metre ruler and connect it to a resistance meter using crocodile clips.
Take a look at their results.
| Length of wire (cm) |
Resistance (Ω) |
Attempt 1 |
Attempt 2 |
Attempt 3 |
Mean |
25 |
8.8 |
8.3 |
8.5 |
8.533 |
50 |
16.2 |
16.1 |
16.4 |
16.4 |
75 |
23.5 |
23.8 |
18.7 |
23.7 |
100 |
30.8 |
31.1 |
31.0 |
31.0 |
(a)
(i) Describe the pattern shown by these results. Use data in your answer.
[2 marks]
(ii) The students made two mistakes when they recorded their results and completed the table. Identify the mistakes and explain what they should have done.
[2 marks]
(iii) The students have correctly handled an anomaly in their results.
Identify the anomaly and explain how it was correctly handled.
[2 marks]
(iv) The students plan to plot a graph of mean resistance against length. What would you expect a graph of these results to look like?
[2 marks]
(b)
(i) The actual mean resistance values are more than expected. Suggest two possible errors with the experiment.
[2 marks]
(ii) For one of the errors, suggest how the experimental procedure could be improved.
[1 mark]
(Total 11 marks)
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