*Question G5A05:
How does an inductor react to AC?*  

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

### AI Response: (may contain errors)  

Inductors react to alternating current (AC) by developing a property called inductive reactance, which opposes changes in current. The inductive reactance ($X_L$) of an inductor is directly related to the frequency of the AC signal and the inductance of the coil.

1. **Correct Answer Explanation (D):**  
   - The formula for inductive reactance is:  
     $$X_L = 2\pi f L$$  
     where:
     - $X_L$ = inductive reactance in ohms
     - $f$ = frequency of the AC in hertz
     - $L$ = inductance in henrys
   - As the frequency ($f$) of the applied AC increases, the inductive reactance ($X_L$) also increases. This is because $X_L$ is directly proportional to the frequency.

2. **Why Other Choices Are Incorrect:**
   - **Choice A:** "As the frequency of the applied AC increases, the reactance decreases" is incorrect because, as shown in the formula, reactance increases with frequency, not decreases.
   - **Choice B:** "As the amplitude of the applied AC increases, the reactance increases" is incorrect because reactance is independent of amplitude. Reactance depends on frequency and inductance, not amplitude.
   - **Choice C:** "As the amplitude of the applied AC increases, the reactance decreases" is incorrect for the same reason as Choice B. Amplitude does not affect reactance.

In summary, the key point is that inductive reactance increases with frequency, which is why Choice D is correct.