*Question G5A03:
Which of the following is opposition to the flow of alternating current in an inductor?*  

*Correct Answer is  D: Reactance*  

### AI Response: (may contain errors)  

In the context of alternating current (AC) circuits, the opposition to the flow of current in an inductor is known as **reactance**. Let's break down why this is the correct answer and why the other choices are incorrect:

1. **Reactance (Correct Answer)**:
   - Reactance is the opposition to the flow of AC caused by inductors and capacitors. For an inductor, this is specifically called **inductive reactance**.
   - The formula for inductive reactance is:
     $$X_L = 2\pi f L$$
     where:
     - $X_L$ = inductive reactance in ohms
     - $f$ = frequency in hertz
     - $L$ = inductance in henrys
   - Inductive reactance increases with frequency and inductance, meaning higher frequencies or larger inductors result in greater opposition to AC.

2. **Conductance (Incorrect Choice)**:
   - Conductance is the reciprocal of resistance and measures how easily electricity flows through a material. It is not related to opposition but rather to facilitation of current flow.
   - Conductance is given by:
     $$G = \frac{1}{R}$$
     where $R$ is resistance in ohms.

3. **Reluctance (Incorrect Choice)**:
   - Reluctance is a concept from magnetism, not electrical circuits. It describes the opposition to magnetic flux in a magnetic circuit, similar to resistance in an electrical circuit.
   - It is not related to the flow of electrical current.

4. **Admittance (Incorrect Choice)**:
   - Admittance is the measure of how easily a circuit or device will allow a current to flow. It is the reciprocal of impedance and is not a form of opposition.
   - Admittance is given by:
     $$Y = \frac{1}{Z}$$
     where $Z$ is impedance in ohms.

In summary, reactance is the correct term for the opposition to AC flow in an inductor, while the other terms relate to different concepts in electrical and magnetic circuits.