*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)  

The correct answer to the question is **C: Reactance**. 

### Explanation of the Correct Answer:
- **Reactance** is the opposition to the flow of alternating current (AC) in a capacitor (and also in inductors). It is a measure of how much a capacitor resists the change in voltage across it when AC is applied. The formula for capacitive reactance ($X_C$) is given by:

$$
X_C = \frac{1}{2 \pi f C}
$$

where:
- $f$ = frequency of the AC signal in hertz (Hz)
- $C$ = capacitance in farads (F)

### Why the Other Choices are Incorrect:
- **A: Conductance**: This refers to the ability of a material to conduct electric current. It is the reciprocal of resistance and does not specifically relate to the opposition of AC in capacitors.

- **B: Reluctance**: This term is used in magnetic circuits to describe the opposition to magnetic flux. It is not applicable to electrical circuits involving capacitors.

- **D: Admittance**: This is the measure of how easily a circuit allows current to flow and is the reciprocal of impedance. While it includes reactance, it does not specifically refer to the opposition caused by a capacitor.

### Summary:
- **Reactance** is the correct term for the opposition to AC in capacitors.
- Conductance, reluctance, and admittance do not specifically describe this phenomenon in the context of capacitors. 

Understanding these terms will help you grasp the concepts of AC circuits and their components better, which is essential for the Extra Class exam.