A copper wire has length L and cross-sectional area A. Its resistance is R. If we halved the length and halved the diameter of the wire, then what would be the resistance of this wire?
Correct answer: C. 2R
- A. 4R
- B. 3R
- C. 2R
- D. R
Explanation
When length is halved, resistance is halved.When diameter is halved, area is divided by 4 (square relationship) hence, resistance is quadrupled. Therefore, (4/2) x R = 2R
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