A wire of resistance R is stretched uniformly four times its length. Its new resistance will be:
Correct answer: A. 16R
- A. 16R
- B. 4R
- C. R/4
- D. R/16
Explanation
When a wire is stretched, its volume remains constant. If the length becomes 4L, the cross-sectional area must become A/4. The new resistance R' = ρ(4L)/(A/4) = 16(ρL/A) = 16R.
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