# Electric circuit problem, finding current through a resistor

1. May 19, 2013

### physics604

1. The diagram attached shows part of an electric circuit. What is the current through resistor R1?

To summarize:
I=6.0 A
R1 = 11.0 Ω
R2 = 33.0 Ω
R3 = 67.0 Ω

R2 and R3 are in parallel, and R1 and R2 and 3 are in parallel.

I know we aren't supposed to attach pictures of questions, but a diagram does make my question a lot easier to understand.

2. Relevant equations

V=IR
IT in series = I1=I2=I3
IT in parallel = I1+I2+I3
RT in series = R1+R2+R3
RT in parallel = [(1/R1)+(1/R2)+(1/R3)]-1

3. The attempt at a solution

Using the resistor laws, I can find resistance of R2 and 3 by (1/33+1/67)-1.

Using Kirchoff's Laws, I know that the resistance coming out has to equal the 6.0 A.

But I don't get how all this information is relevant. The question doesn't give me voltage or any other information and I don't know how to figure out how much current goes through each resistor.

#### Attached Files:

• ###### diagram.PNG
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2. May 19, 2013

### barryj

Notice that ALL of the resistors are in parallel. Find the voltage across all of them, then find the current through each one.

3. May 19, 2013

### Staff: Mentor

What's the net resistance of the circuit?