10.1 Electrostatics with Conductors

Describe the charge distribution within a conductor.

• An ideal conductor is a material in which electrons are able to move freely.
• When a conductor is in electrostatic equilibrium, mutual repulsion of excess charge carriers results in those charge carriers residing entirely on the surface of the conductor.
  • i. In a conductor with a negative net charge, excess electrons reside on the surface of the conductor.
  • ii. In a conductor with a positive net charge, the surface becomes deficient in electrons, and can be modeled as if positive charge carriers reside on the surface of the conductor.
• Excess charges will move to the surface of a conductor to create a state of electrostatic equilibrium within the conductor.
  • i. The time interval over which charges reach electrostatic equilibrium within a conductor is so short as to be negligible.
  • ii. When a conductor reaches electrostatic equilibrium, all points on the surface of the conductor have the same electric potential, and the conductor becomes an equipotential surface.
  • iii. The charge density on the surface of a conductor will be greater where there are points or edges compared to planar areas.
• All excess charges reside on the surface of a conductor, which means there is no net charge in the interior of the conductor, and the electric field is zero within the conductor.
• The electric field is perpendicular to the outer surface of a conductor.
• A conductor can be polarized in the presence of an external electric field. This is a consequence of the conductor remaining an equipotential surface.
• Electrostatic shielding is the process of surrounding an area with a closed, conducting shell to create a region inside the conductor that is free from external electric fields.