. . . equipotential.¹

If we get too close, the resulting electric fields will be strong enough to cause breakdown, which is why one tries to keep wires out from between high voltage plates. Doh.

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. . . Charges:²

[For an interesting commentary, see W. Rindler, Am. J. Phys. 57, 993 (1989).]

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. . . Loop:³

[This is one of the methods used to search for magnetic monopoles in the laboratory; see B. Cabrera, Phys. Rev. Lett. 48, 1378 (1982).]

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