# What Is The Resistivity Of Constantan At 0 Degrees

What is the resistance of a copper wire of 2 km long and 0.50 mm diametre if the resistivity of copper is 1.7 ×10^-6 ohm meter?

R = ρ*l/Awhere R is resistance in ohm, ρ is resistivity in Ω-metre, l is length in metre & A is cross sectional area in m^2.Given,ρ = 1.7 * 10^-6 Ω-metrel = 2,000 metre (2 km)A = π*r^2 = π*(0.0005/2)^2 m^2 = 1.9635 * 10^-7 m^2(Since 0.5 mm= 0.0005 m & Radius is half of diameter)So,R= (1.7 * 10^-6 )* 2000 / (1.9635 * 10^-7) Ωor, R= 17,316.05 Ω or 17.316 kΩ

How to test the resistance of the wire?

This is for a school project and needs to be at GCSE standards, no more advanced than that please!

I conducted an experiment on the resistance of a wire, measuring the voltage and the current on a circuit with a metre long wire and shortening the wire and repeating the experiment until I had all the data I needed. I then used Ohm's law to calculate the resistance of the wire at different lengths and I am currently writing up a conclusion.

However to achieve a higher grade I need to mention a different experiment I could perform to get more reliable data, and that's what I'm asking, what similar yet more reliable practical could I perform in order to get similar results to back up my conclusion (of course, this is hypothetical so I don't need too much detail).