# Homework Help: Circuit Problem -- With only a battery in the circuit, will current flow?

1. Apr 19, 2016

### Faiq

1. The problem statement, all variables and given/known data
Will current flow in an ideal circuit given that there is only an ideal battery in the circuit?

2. Relevant equations
V=IR

3. The attempt at a solution
Since there is no resistance through out the circuit no potential is dropped so no current flows

Last edited by a moderator: Apr 19, 2016
2. Apr 19, 2016

### ProfuselyQuarky

Are you asking if whether a current will flow only if there is a battery?

3. Apr 19, 2016

### Faiq

Yes

4. Apr 19, 2016

### ProfuselyQuarky

Of course. Batteries are the power supply of a circuit. How can there be current flowing through a circuit without any form of power connected to it?

5. Apr 19, 2016

### Faiq

Thanks

6. Apr 19, 2016

### ProfuselyQuarky

Sure . . .

Although I'm curious to know what made you think otherwise?

7. Apr 19, 2016

### Staff: Mentor

Hold on, do you mean a circuit with a battery only, with its + terminal connected to its - terminal via an ideal wire?

8. Apr 19, 2016

### Faiq

No current is flowing right? I was thinking the same but one guy said otherwise and gave no logic behind his reasoning

9. Apr 19, 2016

### Faiq

And the battery doesnt even have internal resistance

10. Apr 19, 2016

### Staff: Mentor

Then this is a case of an unrealizable circuit. The ideal battery will want to drive an infinite amount of current through the wire.

You get a similar problem with an ideal current source with open terminals; it will want to create an infinite potential difference across the terminals in order to drive the required current.

In both cases, in the real world, something's gotta give. Think: FLASH! BANG! SMOKE!

11. Apr 19, 2016

### Faiq

No I am just asking why would current even flow when there's no potential difference across the circuit

12. Apr 19, 2016

### Staff: Mentor

The ideal battery will attempt to make enough current flow in order to realize the battery's specified potential difference. With no resistance, it cannot accomplish this so the current heads off to infinity.

13. Apr 19, 2016

### Faiq

For current to flow from one point to another point, there should be some potential difference but the whole circuit is on the same potential. Why would current flow then?

14. Apr 19, 2016

### ProfuselyQuarky

The OP didn't specify any of that
This sounds familiar

15. Apr 19, 2016

### Faiq

The ideal battery's positive terminal is connected to its negative terminal by an ideal wire

16. Apr 19, 2016

### cnh1995

That is an unrealizable circuit, as gneill said earlier.

17. Apr 19, 2016

### Faiq

I know but I am just curios to why would current even flow when there's no potential difference across the circuit

18. Apr 19, 2016

### cnh1995

Ideal battery tries to maintain a constant potential difference across its terminals. Ideal wires have zero resistance, hence, they try to have 0 potential difference across them. These two opposite behaviors make the circuit unrealizable. One good example gneill gave is of an open circuited current source. Similarly, you can't connect two ideal voltage sources in parallel and two ideal current sources in series. These are unrealizable circuits.

19. Apr 19, 2016

### Faiq

Oh which means that my question is invalid?

20. Apr 19, 2016

### cnh1995

The situation in your question is invalid.

21. Apr 19, 2016

### Tom.G

I=V/R
R=0
ERROR, DIVIDE BY ZERO

22. Apr 21, 2016

### donpacino

Note: In a real circuit, that wire would not have 0 resistance.

It would have a very small resistance, so a large amount of current would flow.

Often when thinking about ideal cases, it can help to think what would happen in a slightly less than ideal case