*Question E5B05:
What is the effect on the magnitude of pure reactance when it is converted to susceptance?*  

*Correct Answer is  D: It is replaced by its reciprocal*  

### AI Response: (may contain errors)  

To understand the effect on the magnitude of pure reactance when it is converted to susceptance, let's break down the concepts involved.

### Correct Answer: It is replaced by its reciprocal

- **Reactance ($X$)** is a measure of how much a circuit element resists the flow of alternating current (AC) due to its inductance or capacitance. It is measured in ohms (Ω).
- **Susceptance ($B$)** is the reciprocal of reactance and is measured in siemens (S). The relationship is given by:

$$
B = \frac{1}{X}
$$

- Therefore, when you convert pure reactance to susceptance, you are indeed replacing it with its reciprocal. The magnitude of susceptance will be the reciprocal of the magnitude of reactance.

### Why the Other Choices are Incorrect:

- **A: It is unchanged**  
  This is incorrect because converting reactance to susceptance involves taking the reciprocal, which changes the value.

- **B: The sign is reversed**  
  This is misleading. While the sign of reactance can be positive (inductive) or negative (capacitive), converting to susceptance does not simply reverse the sign; it changes the value to its reciprocal.

- **C: It is shifted by 90 degrees**  
  This choice confuses the concept of phase shift with the conversion of reactance to susceptance. While reactance and susceptance are related to phase angles in AC circuits, the conversion does not involve a simple 90-degree shift.

### Summary

- Reactance ($X$) and susceptance ($B$) are related through the reciprocal relationship.
- The correct answer is that the magnitude of pure reactance is replaced by its reciprocal when converted to susceptance. 

This understanding is crucial for analyzing AC circuits and their behavior in terms of impedance and admittance.