Interference pattern can be produced by two identical sources. Here the identical sources mean that-

Options

A. their size is same
B. their wavelength is same
C. the intensity of light emitted by them is same
D. the amplitudes of light waves emitted by them are same

Answer

To solve the question regarding the conditions for producing an interference pattern by two identical sources, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding Identical Sources**:
- Identical sources in the context of interference refer to sources that emit waves of the same nature. This means they should have the same frequency and wavelength.

2. **Coherence Requirement**:
- For a proper interference pattern to be formed, the two sources must be coherent. Coherent sources are those that maintain a constant phase difference over time. This is crucial for producing a stable interference pattern.

3. **Wavelength and Frequency**:
- The sources must emit waves of the same wavelength. This is a direct consequence of them being coherent. If the wavelengths are different, the phase difference will change over time, leading to an unstable interference pattern.

4. **Amplitude and Intensity**:
- While the amplitudes of the waves can be different, it is not necessary for the intensities to be the same. The intensity of the light is related to the square of the amplitude, but for interference, the key requirement is the coherence and the same wavelength.

5. **Conclusion**:
- Therefore, the essential condition for two identical sources to produce an interference pattern is that they must have the same wavelength and be coherent.

### Final Answer:
The identical sources mean that they must have the same wavelength and be coherent.