Homework Help: Compound Circuits and resistance in a parallel circuit

1. Nov 11, 2012

bnosam

1. The problem statement, all variables and given/known data
http://imageshack.us/a/img829/1351/circuite.png [Broken]
Find the current through R3 and R2.

The resistance of R2 and R3 are 3.00 Ω, so the total resistance should be 9.00 Ω.

I = 80.0 V / 9.00 Ω = 8.89 A

2. Relevant equations

I = E/R (I think?)

3. The attempt at a solution

Not really sure where to go from here, since this was the first question of this unit and it's a correspondence course and the book doesn't explain compound circuits past a single paragraph.

Any supplemental information or hints you can provide?

Thanks

Last edited by a moderator: May 6, 2017
2. Nov 11, 2012

Staff: Mentor

So far, so good. What's the voltage across R2 and R3?

3. Nov 11, 2012

bnosam

V = I*R

V = (8.89 A) (3.00 Ω) = 26.67 V, right?

4. Nov 11, 2012

Staff: Mentor

Good! Now use that to find the current through each resistor.

5. Nov 11, 2012

bnosam

Awesome man, thanks a lot.

R3 = 26.67 V / 12.00 Ω = 2.22 A

R2 = 26.67 V / 4.00 Ω = 6.67 A