3
\$\begingroup\$

Say I have an open circuit with a battery. I have a wire connected to the negative terminal and a wire connected to the positive terminal. The wires aren't connected.

In this scenario, would their be electron flow for a very short amount of time? Would the electrons from the negative terminal flow through the wire connected to it, since the potential would decrease between the electrons?

To clarify what I mean, consider the first diagram in this image:

enter image description here

In the first diagram there a large amount of electrons in the negative terminal. Would the electrons in the negative terminal distribute themselves through the wire to minimize the force between them?

\$\endgroup\$
3
\$\begingroup\$

Keep in mind that the wire is a metal and thus already has a great deal of free electrons. The battery is not a source of electrons, it's a pump to move what is already there.

Still, you can view the system as a very small capacitor, with the wires being the plates. They would be relatively far apart and have very little surface area so the capacitance would be very very small. So, yes, I think there would be electron transfer, but it would be negligible and it would only last an instant.

\$\endgroup\$
  • \$\begingroup\$ But the battery is a source of electrons. It pumps the electrons in the wire by the anode oxidizing and releasing electrons into the wire which creates an electric field which causes conduction. \$\endgroup\$ – dfg Feb 8 '14 at 23:51
  • \$\begingroup\$ That's your misconception. Electrons moving from the negative terminal of the battery onto the wire don't even necessarily reach the positive terminal. The wire is a full pipe, the electrons themselves are moving, on average, millimeters per hour, the battery is far more of a pump than a source. \$\endgroup\$ – Samuel Feb 9 '14 at 0:02
  • \$\begingroup\$ Right, but if I have a pump connected to a full pipe of water, the water will redistribute itself to minimize the pressure. Does the same thing happen with electricity? \$\endgroup\$ – dfg Feb 9 '14 at 0:15
  • \$\begingroup\$ Yes. You experience this every time to get shocked from a static electricity discharge. Charges equalize. It won't be significant in this case because the negative terminal is not a large collection of electrons, it's not a source, it's just another piece of metal. \$\endgroup\$ – Samuel Feb 9 '14 at 0:21
  • 1
    \$\begingroup\$ Actually, an interesting note about current: the 'electron flow' of current is really just a very slight bias in the movement of the actual electrons. Due to the fact that your wire is not at absolute zero, the electrons are zipping about randomly in all directions. Even with several amps of current in a wire, electrons in the wire are only slightly more likely to move in the direction of the current flow as they are to move in the opposite direction. If they all moved in the same direction, the resulting current in even a very small wire would be many thousands of amps. \$\endgroup\$ – alex.forencich Feb 9 '14 at 10:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.