# Resistance of a wire around the Earth

godiswatching_
Homework Statement:
Homework statement in the image.
Relevant Equations:
$$R=\rho\frac{l}{A}$$
$$l=2\pi r$$

I did (1) Using
$$R_{0}=\rho\frac{l}{A}$$

For (2) I assume the question means that the radius increases by a meter.
So I used $$\bigtriangleup L = 2\pi (r_{E}+1) - l$$
and then I used that L to find the new R. Then I said $$\bigtriangleup R = R-R_{0}$$

Does that seem right? This seems too simple to be right.

$$\bigtriangleup R = 3.4 \cdot 10^{-4} \Omega$$

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Homework Helper
'Too simple' is not an argument ...
What could possible be wrong ?

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godiswatching_
'Too simple' is not an argument ...
What could possible be wrong ?

##\ ##
I don’t see anything wrong with my steps. I think they are all logically sound. It’s more so that I’m paranoid and don’t want to lose points on homework for no reason really.

Homework Helper
PF isn't in the business of stamp-approving homework. It wouldn't help anyone. You do your calculation, get a result and check it. Twice if you want, three times if you are paranoid Have some faith in your work ... ##\ ##

• phinds
Staff Emeritus