1. The problem statement, all variables and given/known data http://img185.imageshack.us/my.php?image=p2827altvk4.gif (b) Calculate the potential difference between points a and b. 3. The attempt at a solution I have solved the circuit using Kirchhoff's laws; I had to solve for the current in the 2 ohm resistor. But I am stuck at this question. I surmised that the potential difference would be using the 2 ohm resistor since we solved for it specifically. I found the potential difference at that resistor, and that yielded the correct answer but I have no clue why. I was wondering if someone could explain this to me? Thanks.