Two sources of waves are called coherent if

Options

A. Both have same amplitude of vibration
B. Both produce waves of same wavelength
C. Both produce waves of the same wavelength having constant phase difference
D. Both produce waves having same velocity

Answer

To determine the conditions under which two sources of waves are called coherent, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Coherence**:
- Coherence refers to the correlation between two wave sources. For two sources to be coherent, they must maintain a consistent relationship over time.

2. **Constant Phase Difference**:
- A key characteristic of coherent sources is that they have a constant phase difference. This means that the difference in phase between the two waves does not change as time progresses.

3. **Same Wavelength**:
- In addition to having a constant phase difference, coherent sources typically produce waves of the same wavelength. This ensures that the waves can interfere constructively or destructively in a predictable manner.

4. **Conclusion**:
- Therefore, two sources of waves are called coherent if they produce waves of the same wavelength and have a constant phase difference.

### Final Answer:
Two sources of waves are called coherent if both produce waves of the same wavelength and have a constant phase difference.

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