Electromagnetic wave consists of periodically oscillating electric and magnetic vectors.

Options

A. in mutually perpendicular planes but vibrating with a phase difference of `pi`
B. in mulually perpendicular planes but vibrating with a phase difference of `(pi)/(2)`
C. in randomly oriented planes but vibrating in phase
D. in mutually perpendicular planes but vibrating in phase.

Explanation

To solve the question regarding electromagnetic waves and their characteristics, we can break down the solution into clear steps:

### Step-by-Step Solution:

1. **Understanding Electromagnetic Waves**:
- Electromagnetic waves are composed of electric (E) and magnetic (B) field vectors that oscillate in space and time.

2. **Characteristics of Electric and Magnetic Vectors**:
- The electric field vector and the magnetic field vector are always perpendicular to each other. This means if the electric field is oscillating in one direction, the magnetic field will oscillate in a direction that is at a right angle (90 degrees) to it.

3. **Phase Relationship**:
- Both the electric and magnetic field vectors oscillate in phase. This means that they reach their maximum and minimum values at the same time.

4. **Visualization**:
- To visualize this, imagine drawing the electric field vector oscillating up and down (let's say along the y-axis) while the magnetic field vector oscillates side to side (along the x-axis). The direction of propagation of the wave would be along the z-axis.

5. **Conclusion**:
- Based on the characteristics of electromagnetic waves, we can conclude that the correct option would be one that states that the electric and magnetic vectors are mutually perpendicular and oscillate in phase.

### Final Answer:
- The correct option is **D**: Both vectors are mutually perpendicular and vibrating in the same phase.

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