At what temperature will the resistance of a copper wire become three times its value at 0oC (Temperature coefficient of resistance for copper = 4 x 10^3? per oC)
Correct answer: C. 500oC
- A. 400oC
- B. 450oC
- C. 500oC
- D. 550oC
Explanation
The correct answer is C: 500oC. To solve this, apply the formula: Rt = R0(1 + αt), where α is the temperature coefficient of resistance. Given α = 4 × 10-3 per oC and Rt = 3R0, we rearrange to find the temperature t: 3 = 1 + 4 × 10-3 × t. Solving for t gives t = 500oC.This calculation shows why 500oC is correct, whereas 400oC and 450oC are too low to achieve the tripling, and 550oC is unnecessarily high.
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