OK doing some physics coursework at the moment where I have to measure the resistivity of Constantan. Anyway, for those who don't know, the resistivity of constantan is 49x10^-8.(adsbygoogle = window.adsbygoogle || []).push({});

Anyway the formula for those who don't know for resistivity is...

RA/l

So anyway at length of 100cm, with a diameter of 0.464mm, I got these readings in a circuit. Current = 0.33, Voltage = 2.13, which gives the resistance as 6.45. (I did repeat readings to get an average but this is just one reading as an example.)

Anyway after finding the Cross-sectional area of the constantan by doing A=pi*r^2. Now to do this, I halve the diameter to get 0.232mm. This is the same as 0.000232m (metres). So after squaring this I get, 5.3824^-8. After multiplying this by pi, I get the cross-sectional area to be 1.69...^-7. Multiply the cross-sectional area by the resistance (6.45) which gives 1.09...^-6. Finally dividing by the length (1metre), which leaves the same answer.

I know this is a lot to read, and I'm asking a lot for help, but please, can you find what I've done wrong, or anything?

I really appreciate all help

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# Homework Help: Resistivity Coursework problem

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