*Question E3A05:
How are the component fields of an electromagnetic wave oriented?*  

*Correct Answer is  C: They are at right angles*  

### AI Response: (may contain errors)  

In an electromagnetic wave, the electric field ($E$) and the magnetic field ($B$) are oriented at right angles to each other and to the direction of wave propagation. This is a fundamental property of electromagnetic waves.

### Explanation:

1. **Correct Answer: C - They are at right angles**
   - The electric field and magnetic field components of an electromagnetic wave are perpendicular to each other. This means they are oriented at 90 degrees relative to each other. Additionally, both fields are perpendicular to the direction in which the wave is traveling. This orthogonal relationship is a key characteristic of electromagnetic waves.

2. **Why the other choices are incorrect:**
   - **A: They are parallel**  
     - If the fields were parallel, they would not form a proper electromagnetic wave. The perpendicular orientation is necessary for the wave to propagate through space.
   - **B: They are tangential**  
     - "Tangential" implies that the fields would be aligned along the same line or surface, which is not the case. The fields must be perpendicular to each other.
   - **D: They are 90 degrees out of phase**  
     - "90 degrees out of phase" refers to a time difference in the oscillation of the fields, not their spatial orientation. In an electromagnetic wave, the electric and magnetic fields oscillate in phase, meaning they reach their maximum and minimum values simultaneously.

### Useful Rule of Thumb:

- **Right-Hand Rule for Electromagnetic Waves:**  
  If you point your thumb in the direction of wave propagation, your index finger in the direction of the electric field, and your middle finger in the direction of the magnetic field, all three will be perpendicular to each other, forming a right-handed coordinate system. This helps visualize the orientation of the fields in an electromagnetic wave.