We say a potential difference moves charges in a resistor.. i want to understand it in terms of field. What charge distribution produces a field in the resistor? True, the cell produces a field.. but it's in the direction along its terminals not across the resistor.


Its all well to say there a difference in potential across the resistor.

  • $\begingroup$ The electric field in the cell opposes the current. That's why you need other process to move the charges in the direction of the current to give them more potential energy that they will then lose as they traverse the circuit. $\endgroup$ – Aaron Stevens May 26 at 10:30
  • $\begingroup$ What moves the charges in the resistor? $\endgroup$ – Neeladri Reddy May 26 at 10:32
  • $\begingroup$ Also, what field do you think it should be, if we are talking about electric potential energy. $\endgroup$ – Aaron Stevens May 26 at 10:32
  • $\begingroup$ You can think of the wires as being part of the terminals of the battery, extending them to the points V and v. $\endgroup$ – The Photon May 26 at 15:23

The cell and wires it connects to produce electric field, not only inside the cell, but also outside. The terminals of the cell are like two points of an electric dipole and their field outside the cell has lines of force that are similar to the wires.

The charges on the wires tune the electric field so that inside the wire, the field is teh same all over the cross-section and points along the wire.

  • $\begingroup$ Can u please tell me how the charges appear on the wire? $\endgroup$ – Neeladri Reddy May 26 at 16:02
  • $\begingroup$ Charges are present everywhere, in the wires as well as in the battery and the resistor. They tend to find each other's opposite so no net positive or negative charge appears on the macroscopic level. But the battery is able to shift this equilibrium and maintain the separation of the positive and negative charges, so parts of the wire surface can become positive, parts can become negative. $\endgroup$ – Ján Lalinský May 26 at 18:01

There is an electric field in the resistor that causes current to flow. Ohms law for the resistor can be written in terms of the field


Where $J$ is the current density, $σ$ is the material conductivity $E$ the electric field. $J$ and $E$ are vectors.

Hope this helps

  • $\begingroup$ Why the down vote $\endgroup$ – Bob D May 26 at 14:35

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