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Dick

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Internal resistance can be calculated from the current that would flow if there were no external resistance. How could you extrapolate that value from your data?

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How could you extrapolate that value from your data?

Good question. I'm trying to figure that out.

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Dick

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A Best fit line?

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Dick

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Yessssss. And what intercept will be of interest?

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x-intercept?

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Dick

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where Ri is internal resistance, Ro - external resistance, E emf and I : current.

E can be measured as open circuit voltage or when the current is zero. In fact if you measure the voltage, there's some current going through, but it is very small and can be negligible. So theoretically, with only one value of Re, you can calculate Ri.

If the circuit involves a battery, it may be more complicated for the concentration overvoltage.

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I took your advice and switched the the axes. Thanks.

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Never mind. I think I got it. Thanks for all of your help.

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Dick

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I seem to be confused at what you want me to graph, now.

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Dick

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The Voltage without external resistors is 5 V

I also have the equation of the Best-fit line for Voltage vs. Current

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Dick

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r = .542 Ω

r = .714 Ω

r = .891 Ω

r = 1.455 Ω

r = .889 Ω

Quite a big difference.

r = .714 Ω

r = .891 Ω

r = 1.455 Ω

r = .889 Ω

Quite a big difference.

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Dick

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I've finally got it, thanks to you. According to my graph, the internal resistance is .5094 Ω.

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