# 4. Electrostatics with Conductors

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4. Electrostatics with Conductors
General statements about E(x) in or near a conductor E is 0 inside the conducting material. E is normal at the surface. The surface charge density is  = 0En . The conductor is an equipotential. (Explain why each statement must be true.) G L Pollack and D R Stump Electromagnetism

4. Electrostatics with Conductors
The Method of Images The image of a charge q in a planar conducting surface is a charge q = – q located at an equal distance on the opposite side of the surface. The image of a charge q in a conducting sphere of radius a is a charge q= – qa/r located at the conjugate point, i.e., at radius r = a2/r. (Explain why the image charge is not real but a useful fiction.) G L Pollack and D R Stump Electromagnetism Chapter 4

4. Electrostatics with Conductors
In some simple, azimuthally symmetric problems involving a spherical conducting boundary, the potential in a charge-free region takes the form where A, B, C, D are constants that will be determined by the boundary conditions. Then the electric field is E = V . (Section 4.3) G L Pollack and D R Stump Electromagnetism