# resistance of a wire.

Discussion in 'Homework Help' started by strantor, Aug 9, 2011.

1. ### strantor Thread Starter AAC Fanatic!

Oct 3, 2010
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It has a little quiz at the end of each chapter. one of the questions is
"A wire is replaced with one that is twice as long and one half the diameter. It's resistance will be:
A. one-fourth
B. four times
C. eight times
D. the same"

My answer was B but it is saying the answer is C. Am I missing something or is the book wrong?

2. ### MrChips Moderator

Oct 2, 2009
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The area of a circle increases as the square of the radius.

strantor likes this.
3. ### strantor Thread Starter AAC Fanatic!

Oct 3, 2010
4,302
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DOH! thanks

$R = \rho \frac{L}{A}$