Two coherent source of light can be obtained by

Options

A. Two different lamps
B. Two different lamps of different power
C. Two different lamps of same power
D. By dividing a wavefront

Answer

To solve the question, "Two coherent sources of light can be obtained by," we will analyze the options provided and determine which one correctly describes how coherent sources can be created.

### Step-by-Step Solution:

1. **Understanding Coherent Sources**:
- Coherent sources of light are defined as sources that emit light waves with the same frequency and a constant phase difference. This means that the light waves produced by these sources will interfere with each other in a predictable manner.

2. **Analyzing the Options**:
- **Option 1: Two different lamps**: Different lamps will emit light of different frequencies and phases, making them incoherent sources. Therefore, this option is incorrect.
- **Option 2: Two different lamps of different power**: Similar to the first option, different lamps will have different frequencies regardless of their power, hence they cannot be coherent. This option is also incorrect.
- **Option 3: Two different lamps of same power**: While the power is the same, the lamps are still different sources and will emit light of different frequencies. Thus, this option is incorrect as well.
- **Option 4: By dividing a wave front**: This method involves using a single coherent light source (like a laser) and splitting its wave front using a device like a beam splitter or by creating two slits in a barrier. This ensures that both resulting sources maintain the same frequency and phase relationship, making them coherent. This option is correct.

3. **Conclusion**:
- The correct answer is that two coherent sources of light can be obtained by dividing a wave front.

### Final Answer:
Two coherent sources of light can be obtained by dividing a wave front.