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MIT Physics 8.02 - Electricity & Magnetism

SECTION : Electrostatics      

SUBJECT: Destroying an Electric Field  

An animation of the destruction of an electric field. We start out with five negative electric charges and five positive charges, separated by a distance L in space. An external agent moves one of the positive charges at constant velocity from its initial position to the position of the negative charges. After doing that, the agent moves the second positive charge in the same manner. The agent continues on with the rest of the positive charges, until all the positive charges are sitting on top of the negative charges. We have color coded the "grass seeds" representation to represent the strength of the electric field. Very strong fields are white, very weak fields are black, and fields of intermediate strength are yellow.

The field lines move in the direction of the energy flow of the electromagnetic field. Over the course of the animation, the strength of the electric field decreases as each positive charge is moved into place. That energy flows into the path along which the charges move, and is being provided to the agent moving the charges at constant speed with the electric field of the other charges. The work done by this agent at the end of this process is equal in magnitude and opposite in sign to the energy originally stored in the electric field.



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