[SOLVED] Change in Electric Potential 1. The problem statement, all variables and given/known data The resistances in the figures A and B are all 7.0 ohms, and the batteries are ideal 13 V batteries. When switch S in figure b is closed, what is the change in the electric potential VR1 across resistor 1? 2. Relevant equations I know that in figure A if S is closed the change in electric potential across R1 is 0. How does the addition of R3 in figure B change this fact? Ohm's Law: V=iR 3. The attempt at a solution I'm not really sure where to begin. I thought the change in electric potential in figure B would be 0 as well. Anybody care to enlighten me?