When AC passes through capacitor the current

Options

A. leads voltage by phase `pi`.
B. remains in phase with voltage .
C. leads voltage by phase `pi//2`.
D. lags voltage by phase `pi//2`

Answer

To solve the question of whether the current leads or lags the voltage when AC passes through a capacitor, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding AC in Capacitors**:
- In an AC circuit with a capacitor, the voltage across the capacitor does not change instantaneously with the current. Instead, the current leads the voltage due to the nature of capacitive reactance.

2. **Drawing the Phase Diagram**:
- We can represent the AC circuit using a phase diagram. In this diagram, we will plot the voltage and current as vectors (phasors) on a graph.
- The current (I) is represented along the horizontal axis (real axis), while the voltage across the capacitor (V_C) is represented along the vertical axis (imaginary axis).

3. **Identifying the Relationship**:
- In a purely capacitive circuit, the current reaches its maximum value before the voltage does. This is because the capacitor charges and discharges, causing the current to flow before the voltage across the capacitor builds up.

4. **Phase Angle Calculation**:
- The phase difference between the current and the voltage in a capacitor is 90 degrees (or π/2 radians). This means the current leads the voltage by π/2 radians.

5. **Conclusion**:
- Therefore, when AC passes through a capacitor, the current leads the voltage by an angle of π/2 radians.

### Final Answer:
The current leads the voltage by an angle of π/2 radians when AC passes through a capacitor.

---