A parallel-plate capacitor of plate area A and plate separation d is connected to a battery through a key. The key is pressed and a steady conduction current begins to flow in the connecting wires.
(a) Define displacement current.
(b) Explain, with reason, why displacement current is said to "flow" in the region between the plates even though the region contains no free charge carriers.
(c) State the modified form of Ampère’s circuital law which takes this current into account.
(d) Briefly describe how the introduction of displacement current removes the inconsistency that arose when the original Ampère’s law was applied to the charging capacitor.