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Home Q & A Board Science-Related Homework Help Physics
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rimrod75 rimrod75
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Posts: 20
Rep: 1 0
11 years ago
The resistivity formula is p=R*(A/L).
So if length of the wire increases, the resistivity gets smaller!

Why would this happen, because it doesn't make sense that a longer wire would have less resistance?

Thanks for clearing this up.
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2 Replies
Replies
wrote...
#1
11 years ago
R in your formula is for total resistance of your sample.

If you simply made the wire longer, then R would also increase.  You can't increase the length of a regular wire while holding R constant. In fact, R should increase exactly enough to keep rho constant.

Resistance (R, measured in ohms) does increase with length for constant material and cross-section.
Resistivity (rho, measured in ohm-meters) will be constant for a given material.
Answer accepted by topic starter
darkshinradarkshinra
wrote...
#2
Posts: 9
Rep: 0 0
11 years ago
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