#Fieldlines zero electric potential free

To calculate the flux through a particular surface, multiply the surface area by the component of the electric field perpendicular to the surface. This is important for deriving electric fields with Gauss' Law, which you will NOT be responsible for where it'll really help us out is when we get to magnetism, when we do magnetic flux.Įlectric flux is a measure of the number of electric field lines passing through an area. It's also a good time to introduce the concept of flux. What we will do is to look at some implications of Gauss' Law. Gauss' Law can be tricky to apply, though, so we won't get into that. The charge accumulates at the pointy ends because that balances the forces on each charge.Ī clever way to calculate the electric field from a charged conductor is to use Gauss' Law, which is explained in Appendix D in the textbook. For charge distributed along a line, the equilibrium distribution would look more like this: This charge would experience a force to the left, pushing it down towards the end. If you look at the second charge from the left on the line, for example, there is just one charge to its left and several on the right. With the line, on the other hand, a uniform distribution does not correspond to equilbrium. The circular conductor is in equilibrium, as far as its charge distribution is concerned. With the circular shape, each charge has no net force on it, because there is the same amount of charge on either side of it and it is uniformly distributed. Charges are distributed uniformly along both conductors. Why does charge pile up at the pointy ends of a conductor? Consider two conductors, one in the shape of a circle and one in the shape of a line. A charge experiencing that field would move along the surface in response to that field, which is inconsistent with the conductor being in equilibrium. If it wasn't, there would be a component of the field along the surface.

#Fieldlines zero electric potential free

There are plenty of free electrons inside the conductor (they're the ones that are canceling out the positive charge from all the protons) and they don't move, so the field must be zero.Ī similar argument explains why the field at the surface of the conductor is perpendicular to the surface. If the field wasn't zero, any electrons that are free to move would.

They also distribute themselves so the electric field inside the conductor is zero. To do this they move to the surface of the conductor. The excess electrons repel each other, so they want to get as far away from each other as possible. Consider a negatively-charged conductor in other words, a conductor with an excess of electrons. Let's see if we can explain these things.

charge accumulates, and the field is strongest, on pointy parts of the conductor.

the electric field at the surface of the conductor is perpendicular to the surface.

the electric field is zero within the solid part of the conductor.the excess charge lies only at the surface of the conductor.At equilibrium, the charge and electric field follow these guidelines: Basically, when you charge a conductor the charge spreads itself out.

The electric field near conductors The electric field near conductorsĪ conductor is in electrostatic equilibrium when the charge distribution (the way the charge is distributed over the conductor) is fixed.