1. The problem statement, all variables and given/known data I have two questions. Both questions are in the picture below. Dont mind my workings lol http://img163.imageshack.us/img163/5680/scanpic0001qe.jpg [Broken] Ans to the 1st qn: C The potential difference across the 3ohm resistor is zero. Thus, it can be considered that the 4ohm and 2 ohm resistor is in parallel with the 8ohm and 4 ohm resistor. So the effective resistance between A and B is (1/(4+2) +1/(8+4))^-1 = 4ohms But my question is, why is the p.d. across 3 ohm resistor zero? Ans to the 2nd qn: C The effective e.m.f is 1.5v and effective internal resistance is (1/3 + 1/3+1/3)^-1 = 1ohms E=I(R+r) 1.5=I(10 + 1) I=0.14A And my question is, how does the circuit work? Why do we have the consider all of the internal resistance of the batteries?