alleryA wire is stretched to twice its original length while keeping its volume constant. Its new resistance is:
A4 times the original
B2 times the original
Cunchanged
Dhalf the original
Answer & Solution
Correct answer: A. 4 times the original
Volume is constant, so doubling the length halves the area.
R = ρl/A scales as l/A → (2)/(½) = 4 times the original.
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