# Wire and resistor in parallel

1. Jan 19, 2015

### joel amos

• Member warned about lack of template
If a "normal" looking wire and a resistor are in parallel on a simple circuit diagram, will any current pass through the resistor?

2. Jan 19, 2015

### Bystander

Yes, E/R. It's going to be a very small current since the voltage drop across the wire is going to be very small.

3. Jan 19, 2015

### joel amos

For the purpose of the problem, do you think the current through the resistor would be considered negligible?

4. Jan 19, 2015

### Bystander

You haven't included a problem statement? I've no way of knowing.

5. Jan 19, 2015

### joel amos

6. Jan 19, 2015

### Bystander

No difference. You'll want to recalculate R1 it that's actually a "140" I'm reading. As far as the short circuit around R2 for this problem, yes, call it zero.

7. Jan 19, 2015

### joel amos

I'm attempting this by finding the voltage drops at the two known resistors. However, R2 has a voltage drop of .02 A (1,000 Ω) = 20 V. How is this possible, as the battery is only 5 V?

8. Jan 19, 2015

### Bystander

The wire has a nearly zero resistance. It is in parallel with R2. What is the resistance of two resistors in parallel? When one is the next thing to zero?

9. Jan 19, 2015

### joel amos

Ooo. I thought we'd established that the current through the wire was nearly 0.

I'd say that the resistance would be very small.

10. Jan 19, 2015

### Bystander

Yes. Sorry, I thought you'd picked up that the wire is carrying nearly all the current, and that the current through the resistor would be just whatever it carries for the very small voltage drop across that length of wire.

11. Jan 19, 2015

### joel amos

I got 130 Ω after solving the following equation for R1:
3.5 V = .02 A (120 Ω + R1)

12. Jan 19, 2015

### Bystander

That's good.

13. Jan 19, 2015

### joel amos

Awesome! Thanks for the help!