CONDUCTORS, DIELECTRICS, AND
CAPACITANCE
CONDUCTORS, DIELECTRICS, AND
CAPACITANCE
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Thus under static conditions, the following conclusions can be made
about a perfect conductor:
1. No electric field may exist within a conductor; that is,
2. Since E = 0, there can be no potential difference between any two
points in the conductor; that is, a conductor is an equipotential body.
3. The electric field E can be external to the conductor and normal to
its surface; that is
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An important application of the fact that E = 0 inside a conductor is
in electrostatic screening or shielding.
If conductor A kept at zero potential surrounds conductor B as
shown in the figure, B is said to be electrically screened by A from
other electric systems, such as conductor C, outside A. Similarly,
conductor C outside A is screened by A from B.
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Thus conductor A acts like a screen or shield and the electrical
conditions inside and outside the screen are completely
independent of each other.
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Example:
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