If a wire is drawn out to 3 times its original length, by how many times its resistance is expected to be increased?
Answer (1)
17th Dec, 2021
Since volume is same in both cases => l'A'=l×A => 3l×A'=l×A =>A' =A/3
R'=ρ×l'/A' = (ρ×3l)/ (A/3) =>R'=9ρl/A = 9R
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resistance increases by 9 times
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