Light waves travels in vacuum along the X-axis. Which of the following may represent the wavefronts?

Options

A. x = c
B. y =c
C. z =c
D. x + y+ z =c.

Answer

To solve the question regarding which of the given options may represent the wavefronts of light waves traveling along the X-axis, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Wavefronts**:
- A wavefront is defined as the locus of points that are in the same phase of a wave. For light waves traveling in a straight line, the wavefronts are perpendicular to the direction of wave propagation.

2. **Identify the Direction of Propagation**:
- According to the question, the light waves are traveling along the X-axis. This means the wavefronts must be perpendicular to the X-axis.

3. **Analyze the Given Options**:
- We need to evaluate each option to determine if it represents a wavefront perpendicular to the X-axis.

- **Option 1: x = c**:
- This represents a vertical plane parallel to the YZ-plane. Since it is perpendicular to the X-axis, this can represent a wavefront.

- **Option 2: y = c**:
- This represents a horizontal plane parallel to the XZ-plane. Since it is parallel to the direction of wave propagation (X-axis), it cannot represent a wavefront.

- **Option 3: z = c**:
- This also represents a horizontal plane parallel to the XY-plane. Similar to option 2, it is parallel to the direction of wave propagation and cannot represent a wavefront.

- **Option 4: x + y + z = c**:
- This represents a plane in three-dimensional space. It does not correspond to a plane that is perpendicular to the X-axis, so it cannot represent a wavefront.

4. **Conclusion**:
- The only option that represents a wavefront perpendicular to the direction of wave propagation (X-axis) is **Option 1: x = c**. Therefore, the correct answer is that the wavefronts can be represented by option 1.

### Final Answer:
- The wavefronts may be represented by **Option 1: x = c**.