A small signal voltage V(t) = V0 sin ωt is applied across

A small signal voltage V(t) = V₀ sin ωt is applied across an ideal capacitor C :

1. Current I (t), lags voltage V(t) by 90°.
2. Over a full cycle the capacitor C does not consume any energy from the voltage source.
3. Current I (t) is in phase with voltage V(t).
4. Current I (t) leads voltage V(t) by 180°.

As we know, power P = V_rms · I_rms cosφ as cosφ = 0
(∵ φ = 90°)
∴Power consumed = 0 (in one complete cycle)