Question

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

Answer 1

The reactance of a capacitor is X_C = \(\cfrac{1}{2\pi f C}\), where f is the frequency of the AC supply and C is the capacitance of the capacitor. For very high frequency, f, X_C is very small. Hence, for very high frequency AC supply, a capacitor behaves like a pure conductor.