Current flowing in a battery is null?

[A13235378]

Homework Statement

Potential difference between A and B. I just have a doubt. Is the current flowing in the 4V battery null? Yes or not? Why?

Relevant Equations

U= RI

 

[DaveE]

Imagine that you are an electron leaving the - side of the battery. How would you get to the + side?

 

[haruspex]

It depends whether this is very shortly after connecting up. If not, see @DaveE's response.

 

[DaveE]

It depends whether this is very shortly after connecting up. If not, see @DaveE's response.

Very shortly, considering there aren't any energy storage elements in the circuit.

I'd bet $100 this is is a DC analysis problem. In which case your response is confusing to the student. Not necessarily wrong, but probably not helpful.

 

[rude man]

Imagine that you are an electron leaving the - side of the battery. How would you get to the + side?

You wouldn't. The electrons all go from the + side to the - side.
(I am probably being petty but ...).

And BTW the answer is the non-conservative electric field set up by the emf of the battery which points from - to + and cancels the conservative E field set up by the charge migration which points from + to -.

 

[DaveE]

The electrons all go from the + side to the - side.

Again, not helpful to the OP.

edit: Oh, yea, also wrong. Electrons have negative charge and are not attracted to the (relatively) negative potential at the - side. [Curse you, Ben Franklin!]

 

[rude man]

Actually, we all missed the OP's point and question.
The current in the 4V battery is indeed zero.
Hint: can you find a loop including the 4V battery?

 

[DaveE]

Actually, we all missed the OP's point and question.
The current in the 4V abttery is indeed zero.

Not all of us. We also didn't give the answer away without dialog or dealing with the question "Why?".