I'm doing a few practicals at home this summer, and the one that is bugging me is about EMF. I have measured voltage and current at different resistances across a 4,5 V battery, and made a graph. But to find the emf, am I supposed to take the slope of the graph, or the gradient? Or is that the same, aka the derivative? English isn't my first language, but I go to an English school, so...(adsbygoogle = window.adsbygoogle || []).push({});

My graph gives a function y=-1,26x + 5,772. Is it possible for the slope to be negative, and thus the emf? I have current at x-axis and voltage at y-axis.

Thanks for all the help, I hope this doesn't seem like I want you to do my homework for me ^^

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# Homework Help: EMF and Internal Resistance

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