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A wire is elongated by 0.1%. What happens to its electrical resistance?

1. It increases by 0.2%
2. It decreases by 0.2%
3. It decreases by 0.05%
4. It increases by 0.05%

Correct answer: It increases by 0.2%

Solution

When a wire is elongated, its length increases while its cross-sectional area decreases. Since resistance is directly proportional to length and inversely proportional to area, the overall effect leads to an increase in resistance, which in this case is calculated to be 0.2%.

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