German silver wire has a cross-sectional area of 2.047 x 10^-3 cm^2. How many meters are needed to make a resistance of 100 (omega)?

I can't find the resistivity of German silver wire. I've googled a few places, but each one gives me a different number.

Can you please tell me what the resistivity is? I need it to plug into R= resistivity (length)/area, solving for length.

2 answers

You are finding different values because there is no single composition for "German silver". That is why you are finding different values for the resisitivity.

According an one online source about alloys:

<<German silver varies in composition, the percentage of the three elements ranging approximately as follows: copper, from 50% to 61.6%; zinc, from 19% to 17.2%; nickel, from 30% to 21.1%. The proportions are always specified in commercial alloys.>>

I recommend that you take an average value of the ones you have found.
According to http://www.radio-electronics.com/info/formulae/resistors/resistivity/resistivity_table.php ,
the range of resisitivity for German silver (for different alloy compositions) is
1.6 to 4.0 * 10^-6 ohm meters.

So I'd use 2.8*10^-5 ohm-m