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The radius (r), length (ℓ) and resistance (R) of a metal wire was measured in the laboratory as r = (0.35 ± 0.05) cm R = (100 ± 10) ohm ℓ = (15 ± 0.2) cm The percentage error in resistivity of the material of the wire is:
- 35.6%
- 39.9%
- 25.6%
- 37.3%
Correct answer: 39.9%
Solution
The percentage error in resistivity is calculated using the formula that combines the errors from the radius, length, and resistance measurements. Given the significant contributions of the uncertainties in these measurements, the resulting percentage error of 39.9% accurately reflects the combined effects of these uncertainties on the resistivity calculation.
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