IF Young's experiment is performed using two separate identical sources of light instead of using two slits and one light source then the

Options

A. Interference fringes will be darker
B. Interference fringes will be higher
C. Fringes will not be obtained
D. Constrast between bright and dark fringes increases

Answer

To solve the question regarding Young's experiment performed using two separate identical sources of light instead of using two slits and one light source, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Young's Experiment**:
Young's double-slit experiment demonstrates the phenomenon of interference of light. It requires two coherent light sources (or slits) that produce light waves with a constant phase difference.

**Hint**: Recall the basic setup of Young's experiment and the role of coherence in producing interference patterns.

2. **Identifying the Sources**:
In the modified setup, we are using two separate identical light sources instead of two slits. Each source emits light waves independently.

**Hint**: Consider the nature of the light emitted from two separate sources and how it differs from light passing through slits.

3. **Coherence Requirement**:
For interference to occur, the light waves from the two sources must be coherent. This means they should have a constant phase difference over time. However, two separate sources do not guarantee this condition.

**Hint**: Think about what coherence means and why it is essential for interference patterns.

4. **Phase Difference and Path Difference**:
Since the two sources are independent, the phase difference between the waves they emit will not remain constant. It will vary with time due to the different emission times of photons from each source.

**Hint**: Reflect on how the phase difference changes when two sources are not synchronized.

5. **Conclusion on Interference**:
Because the phase difference is not constant, there will be no stable interference pattern (fringes) observed on the screen. The light waves will not constructively or destructively interfere in a predictable manner.

**Hint**: Summarize the conditions necessary for observing interference and how the lack of coherence affects the outcome.

6. **Final Answer**:
Therefore, if Young's experiment is performed using two separate identical sources of light, there will be no interference fringes observed.

### Summary:
In conclusion, the key takeaway is that the requirement for coherent sources is crucial for observing interference patterns in Young's experiment. Using two separate light sources fails to meet this requirement, leading to the absence of interference fringes.