Practice question · Multiple choice
Why was Ampere’s law inconsistent before Maxwell added the displacement current?
Hints
- Think about a loop round the wire feeding a charging capacitor.
- One surface is pierced by the wire; another bulges between the plates and is pierced by nothing.
Show the answer
A. Ampère’s law gave different answers for two surfaces sharing one loop
Why
For a charging capacitor, a flat surface catches the wire’s current while a bulging one catches none, yet both share the same boundary loop. The displacement current supplies the missing contribution, since is changing between the plates.
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