*Question G5A04:
Which of the following is opposition to the flow of alternating current in a capacitor?*  

*Correct Answer is  C: Reactance*  

### AI Response: (may contain errors)  

In the context of alternating current (AC) circuits, the opposition to the flow of current in a capacitor is known as **reactance**. Let's break down why this is the correct answer and why the other choices are incorrect:

1. **Correct Answer: Reactance (C)**
   - **Reactance** is the opposition to the flow of AC caused by capacitors and inductors. For a capacitor, the reactance is specifically called capacitive reactance.
   - The formula for capacitive reactance ($X_C$) is:
     $$X_C = \frac{1}{2\pi f C}$$
     where:
     - $f$ is the frequency in hertz (Hz)
     - $C$ is the capacitance in farads (F)
   - As frequency increases, capacitive reactance decreases, meaning the capacitor allows more AC to pass through.

2. **Why the Other Choices are Incorrect:**
   - **Conductance (A):** This is the reciprocal of resistance and measures how easily electricity flows through a material. It is not related to the opposition caused by capacitors.
   - **Reluctance (B):** This term is used in the context of magnetic circuits, not electrical circuits. It describes the opposition to magnetic flux, not electrical current.
   - **Admittance (D):** This is the reciprocal of impedance and measures how easily a circuit allows AC to flow. While related to reactance, it is not specifically the opposition caused by a capacitor.

In summary, capacitive reactance is the specific type of opposition to AC flow in a capacitor, making "Reactance" the correct choice.