1. The problem statement, all variables and given/known data HI! IB physics exams coming up and I'm having real trouble with potentiometers. The two questions I'm posing are in the attachment along with a picture of the circuit they include. 3. The attempt at a solution What I'm having trouble with is the 2nd question, What is the maximum reading of the ammeter? Assuming that I rearrange the voltmeter and ammeter so they're in the right position, I haven't got much of a clue of how to figure this one out. I think this ties in with my poor understanding of potentiometers. I've looked at the answers to find it's 12V / 15, when the resistance of the variable resistor (or potentiometer?) is at its maximum resistance. I would've thought that the voltage across the lamp would be greatest at this setting. But i don't understand how the current= 12V/15. Since the filament lamp and the variable resistor have different resistances won't the current be different in each? If any kind soul could shed some/any light on this problem or perhaps help me a little with potentiometers and why at max. resistance= max current through lamp I'd be eternally grateful. Thanks!