- #1

Krushnaraj Pandya

Gold Member

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## Homework Statement

Four identical cells each having emf E and internal resistance r are connected in series to form a loop abcd as shown in figure (picture 1). Find potential difference across ab and ac.

2. Homework Equations

2. Homework Equations

V=IR

equations for combination of cells and resistances

## The Attempt at a Solution

this is the circuit diagram-(picture 2. left for across ab and right one for across ac), I can find equivalent resistance easily, what confuses me is the sign of the emf- for ab three cells are sending current in one direction while one is in the opposite direction. So using +E for three and -E for one I get the answer -E/2 across ab but the correct answer is E/2. I think there's a fundamental mistake in my understanding of emf so I'd be grateful if someone can explain it to me in an simple, intuitive way. Thank you.