*Question G5A06:
How does a capacitor react to AC?*  

*Correct Answer is  A: As the frequency of the applied AC increases, the reactance decreases*  

### AI Response: (may contain errors)  

A capacitor reacts to alternating current (AC) in a specific way that is determined by its reactance, which is a measure of how much the capacitor resists the flow of AC. The reactance of a capacitor ($X_C$) is given by the formula:

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

where:
- $X_C$ = capacitive reactance in ohms
- $f$ = frequency of the AC in hertz
- $C$ = capacitance in farads

### Explanation of the Correct Answer (A):
- **Correct Answer: A** - As the frequency of the applied AC increases, the reactance decreases.
  - From the formula, you can see that as the frequency $f$ increases, the denominator increases, which causes $X_C$ to decrease. This means that higher frequencies allow more current to flow through the capacitor, making it "easier" for AC to pass.

### Explanation of the Incorrect Answers:
- **B: As the frequency of the applied AC increases, the reactance increases.**
  - This is incorrect because, as explained, increasing frequency decreases the capacitive reactance.

- **C: As the amplitude of the applied AC increases, the reactance increases.**
  - This is incorrect because the reactance of a capacitor is independent of the amplitude (voltage) of the AC signal. Reactance only depends on frequency and capacitance.

- **D: As the amplitude of the applied AC increases, the reactance decreases.**
  - This is also incorrect for the same reason as C. The reactance does not change with the amplitude of the AC signal.

### Summary:
- The key takeaway is that a capacitor's reactance decreases with increasing frequency, allowing more AC current to flow. The reactance is not affected by the amplitude of the AC signal. Understanding this relationship is crucial for working with capacitors in AC circuits.