Question

Answer in brief.

For a very high-frequency AC supply, a capacitor behaves like a pure conductor. Why?

Answer 1

`"X"_"C" = 1/(2pi"fC")` is the reactance of a capacitor, where f is the frequency of the AC supply and C is the capacitance of the capacitor. For extremely high frequencies, f, X_C is extremely small. As a result, for a very high-frequency alternating current supply, a capacitor behaves like a pure conductor.