Question

A capacitor acts as an infinite resistance for

(a) DC
(b) AC
(c) DC as well as AC
(d) neither AC nor DC

Answer 1

(a) DC

For a DC source, ω = 0. So, the reactance of the capacitance is given by,
$X_C=\frac{1}{\omega C}=\frac{1}{0}=\infty$