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.
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%