Charges in a Conductor

  • Charge is free to move until the E=0

    oo Negative e ectric charges are given inside a conductor. Coulomb force (repulsive force) works for each charge. Distribution Of electric charges on the charged conductive sphere. The e ectric charges are distributed on the conductor surface and there is no electric charge inside the conductor.

  • All charge resides at surface

    .103üt7

  • Field lines are perpendicular to the surface

    Field weakest E = D inside Field strongest (d) Electric field & charge distribution around a pear-shaped conductor

Electric Field at the Surface of a Conductor

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image162.png

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image163.png

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image164.png

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image165.png

  • E increases as r σ increases.

Hollow Conductors

Hollow conductor (a) (b) (c) (d) Figure 24.20 An experiment showing that any charge trans- ferred to a conductor resides on its surface in electrostatic equilibrium. The hollow conductor is insulated from ground, and the small metal ball is supported by an insulating thread.

o o o O o o o o 9 o o o o Faraday Cage o Electrical Field The charged particles in the wall Of the Faraday cage respond to an applied electrical field. o o Metal wall o o o o o o o o o Faraday Cage in the absence Of an electrical field. Electrical fields generated inside the wall cancel out the applied field, neutralizing the interior of the cage.

Example 1: Conducting Spheres Connected by a Wire

C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image168.png

  • Two conducting spheres, A and B, are placed a large distance from each other. The radius of Sphere A is 5 cm, and the radius of Sphere B is 20 cm. A charge Q of 200 nC is placed on Sphere A, while Sphere B is uncharged. The spheres are then connected by a wire. Calculate the charge on each sphere after the wire is connected

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image169.png

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image170.png

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image171.png

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image172.png

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image173.png

  • C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image174.png

2004 Free Response Question

Conductor E\&M. 1. r2 111 11 1 0+1 •d •a Conductor Cross Section The figure above left shows a hollow, infinite, cylindrical, uncharged conducting shell of inner radius rl and outer radius r2 . An infinite line charge of linear charge density +1 is parallel to its axis but off center. An enlarged cross section of the cylindrical shell is shown above right. (a) On the cross section above right, i. sketch the electric field lines, if any, in each of regions I, Il, and Ill and ii. use + and — signs to indicate any charge induced on the conductor. (b) In the spaces below, rank the electric potentials at points a, b, c, d, and e from highest to lowest (1 = highest potential). If two points are at the same potential, give them the same number.

C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image176.png

Nonconductor Nonconductor Cross Section (c) The shell is replaced by another cylindrical shell that has the same dimensions but is nonconducting and carries a uniform volume charge density +P . The infinite line charge, still of charge density +1 , is located at the center of the shell as shown above. Using Gauss's law, calculate the magnitude of the electric field as a function of the distance r from the center of the shell for each of the following regions. Express your answers in terms of the given quantities and fundamental constants.

C:\\266298A5\\73477446-49B2-471B-AFDD-BCD03931DCDD\_files\\image178.png

results matching ""

    No results matching ""