Example 1 · difficulty 3/5
An ideal AC circuit consists of a source connected to a pure capacitor alone. The average power delivered by the source over one complete cycle is:
- A. zero, because the current leads the voltage by π/2 so cos φ = 0
- B. equal to Vrms × Irms, since the capacitor continuously stores energy
- C. equal to Vrms × Irms / 2, as the average of sin squared over a cycle is one-half
- D. non-zero and directly proportional to the capacitance C