*Question E4E08:
What current flows equally on all conductors of an unshielded multiconductor cable?*  

*Correct Answer is  B: Common-mode current*  

### AI Response: (may contain errors)  

In the context of an unshielded multiconductor cable, the type of current that flows equally on all conductors is known as **common-mode current**. Here's why:

### Explanation:

1. **Common-mode current (Correct Answer)**:
   - **Definition**: Common-mode current is the current that flows in the same direction on all conductors of a cable relative to a common reference point, usually ground.
   - **Characteristics**: It is often caused by external electromagnetic interference or imbalances in the system. Since it flows equally on all conductors, it does not contribute to the differential signal between the conductors.

2. **Differential-mode current (Incorrect Choice)**:
   - **Definition**: Differential-mode current is the current that flows in opposite directions on a pair of conductors.
   - **Characteristics**: It is the desired signal in most communication systems, as it represents the actual data being transmitted. It does not flow equally on all conductors, hence it is not the correct answer.

3. **Reactive current only (Incorrect Choice)**:
   - **Definition**: Reactive current is associated with the reactive components of impedance, such as inductors and capacitors, and is part of the alternating current that does not contribute to real power.
   - **Characteristics**: Reactive current is not specifically related to the mode of current flow on conductors (common or differential) and does not describe a current that flows equally on all conductors.

4. **Magnetically-coupled current only (Incorrect Choice)**:
   - **Definition**: Magnetically-coupled current refers to current induced in a conductor due to magnetic fields from nearby currents.
   - **Characteristics**: While magnetic coupling can induce currents, it does not specifically describe a current that flows equally on all conductors of a cable.

### Summary:
- **Common-mode current** is the correct answer because it describes the scenario where current flows equally on all conductors of an unshielded multiconductor cable.
- The other options describe different types of current flow or phenomena that do not match the condition of equal current on all conductors.