Uniquedude
New member
- Nov 7, 2011
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Guys, I just learnt about current and terminal pd, and emf and all the rest of it. We learnt that a current against terminal pd graph has a negative slope, with the y-intercept being the emf of the battery.
The only thing I don't understand is why is the slope negative? I know V = E - Ir, and so the gradient is negative, but what happened to V=IR, where current and potential difference are directly proportional? How do both of these formulas exist - they seem to contradict each other? Or have I just got it wrong? Am I confused because I am getting terminal voltage and voltage mixed up?
Any help will be much appreciated!
The only thing I don't understand is why is the slope negative? I know V = E - Ir, and so the gradient is negative, but what happened to V=IR, where current and potential difference are directly proportional? How do both of these formulas exist - they seem to contradict each other? Or have I just got it wrong? Am I confused because I am getting terminal voltage and voltage mixed up?
Any help will be much appreciated!