*Question T6A07:
What electrical component is typically constructed as a coil of wire?*  

*Correct Answer is  D: Inductor*  

### AI Response: (may contain errors)  

The correct answer is **D: Inductor**.

### Explanation of the Correct Answer:
- An **inductor** is an electrical component that is typically constructed as a coil of wire. When current flows through the coil, it creates a magnetic field around it. Inductors are used in various applications, including filtering, energy storage, and tuning circuits.

### Why the Other Choices are Incorrect:
- **A: Switch**  
  A switch is a device used to open or close a circuit. It does not have a coil structure and is typically made of mechanical or electronic components.

- **B: Capacitor**  
  A capacitor stores electrical energy in an electric field and is usually made of two conductive plates separated by an insulating material. It does not involve a coil of wire.

- **C: Diode**  
  A diode is a semiconductor device that allows current to flow in one direction only. It is not constructed as a coil of wire but rather from semiconductor materials.

### Useful Formulas or Rules of Thumb:
- The inductance of a coil can be calculated using the formula:  
$$L = \frac{N^2 \cdot \mu \cdot A}{l}$$  
where:
  - $L$ = inductance in henries (H)
  - $N$ = number of turns in the coil
  - $\mu$ = permeability of the core material (H/m)
  - $A$ = cross-sectional area of the coil (m²)
  - $l$ = length of the coil (m)

This formula helps in understanding how the physical characteristics of an inductor affect its inductance.