Hello everyone, i'm confused, i know the loop rule and the sum of the Potential differences is 0 in a closed circuit but I need to find the Va-Vb of the circuit. Here is the picture: http://www.webassign.net/hrw/hrw7_27-40.gif and here is the info:(adsbygoogle = window.adsbygoogle || []).push({});

the resistances are R1 = 1 , R2 = 2.2 , and the ideal batteries have emfs E1 = 2.0 V, and E2 = 3 = 3 V.

Now i'm confused on how far I calculate, like I tried just going from Va to Vb, and it was wrong i did the following:

Va + R2E2 - E2 = Vb;

Va-Vb = -R2E2+E2 = -3.6;

Also i had another question, I know the direction of the current because E2 > E1, so the direction should flow counter clockwise, now when I run into any kind of resistor do I always use the current of the stronger battery? Like for instance:

If i go from a counter clockwise to b, When i run into the Resistors R1 and R1 again at the bottom, do i still use E2*R1, and never use E1*R1 because E1 is weaker then E2? Thanks.

I also tried to go all the way around a to b, and then back to a counter clockwise and got the following:

Va - R1E2 - E1 - R1E2 + Vb + E2 - E2R2 = 0;

but i ended up with Va + Vb = R1E2 + E1 + R1E2 - E2 + E2R2 = 11.6V, also wrong!

**Physics Forums - The Fusion of Science and Community**

# Finding potential difference of Va-Vb, circuits.

Have something to add?

- Similar discussions for: Finding potential difference of Va-Vb, circuits.

Loading...

**Physics Forums - The Fusion of Science and Community**