The capacitive reactance in an A.C. circuit is

Options

A. effective resistance due to capacitor
B. effective wattage
C. effective voltage
D. none of the above

Answer

To solve the question regarding the capacitive reactance in an A.C. circuit, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept**:
Capacitive reactance (Xc) is a measure of how much a capacitor resists the flow of alternating current (A.C.). It is an important concept in A.C. circuits.

2. **Formula for Capacitive Reactance**:
The formula for capacitive reactance is given by:
\[ X_c = \frac{1}{\omega C} \]
where:
- \(X_c\) is the capacitive reactance,
- \(\omega\) is the angular frequency of the A.C. source, and
- \(C\) is the capacitance of the capacitor.

3. **Understanding Angular Frequency**:
Angular frequency (\(\omega\)) is related to the frequency (f) of the A.C. source by the equation:
\[ \omega = 2\pi f \]
This means that as the frequency increases, the angular frequency also increases.

4. **Analyzing the Effect of Capacitance**:
From the formula \(X_c = \frac{1}{\omega C}\), we can see that:
- If the capacitance \(C\) increases, the capacitive reactance \(X_c\) decreases.
- If the angular frequency \(\omega\) increases, the capacitive reactance \(X_c\) also decreases.

5. **Conclusion**:
The capacitive reactance in an A.C. circuit effectively restrains the flow of current depending on the values of capacitance and frequency. Therefore, it is a crucial factor in determining how capacitors behave in A.C. circuits.

### Final Answer:
The capacitive reactance in an A.C. circuit is given by the formula \(X_c = \frac{1}{\omega C}\).