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## Homework Statement

When a metal rod is heated, not only its resistance but also its length and its cross-sectional area change. The relation R = L/A suggests that all three factors should be taken into account in measuring at various temperatures.

(a) If the temperature changes by 5.0 C°, what percentage changes in R, L, and A occur for a copper conductor? The coefficient of linear expansion is 1.7 10-5/K.

## Homework Equations

delta L = L initial (delta T) (alpha)

R = density L/A

## The Attempt at a Solution

I got the answer to the percentage changes of L and A using the equation

L = L initial (delta T) alpha.

I tried to plug those answers into the equation R = density L/A which gives the answer.5

Unfortunately that answer is wrong and and now I am currently lost.

The percent changes of L and A are:

delta L / L initial = .0085%

delta A / A initial = .017%