A student carries out an experiment to determine the resistivity of a metal wire - AQA - A-Level Physics - Question 8 - 2018 - Paper 1
Question 8
A student carries out an experiment to determine the resistivity of a metal wire. She determines the resistance from measurements of potential difference between the... show full transcript
Worked Solution & Example Answer:A student carries out an experiment to determine the resistivity of a metal wire - AQA - A-Level Physics - Question 8 - 2018 - Paper 1
Step 1
A current
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Answer
The uncertainty in the current measurement contributes to the overall uncertainty in resistivity, but it is relatively small.
Step 2
B diameter
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Answer
The diameter measurement influences the cross-sectional area significantly. A small percentage uncertainty in diameter results in a larger percentage uncertainty in calculated resistivity because area is squared in the formula.
Step 3
C length
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The length measurement affects the resistivity linearly. However, a 1% uncertainty in length does not have as significant an impact as in the area related to diameter.
Step 4
D potential difference
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The potential difference measurement also holds an uncertainty, but since it is only part of the formula, its impact is not as significant as that of diameter.
Step 5
Conclusion
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Answer
Therefore, the measurement that gives the largest uncertainty in the calculated value of resistivity is the diameter of the wire.
