Assertion : Interference is not observed if the two coherent slit sources are broad.
Reason : A broad source is equivalent to many narrow slit sources.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To solve the question, we need to analyze the assertion and the reason provided.

### Step 1: Understanding the Assertion
The assertion states that "Interference is not observed if the two coherent slit sources are broad."

- **Explanation**: Interference patterns are typically observed when coherent sources are used. Coherent sources maintain a constant phase difference, which is essential for producing a clear interference pattern. However, when the sources are broad, they can produce overlapping patterns that are not distinct. Thus, while interference may occur, it is not observable as a clear pattern.

### Step 2: Analyzing the Reason
The reason states that "A broad source is equivalent to many narrow slit sources."

- **Explanation**: A broad source can indeed be thought of as a collection of many narrow sources. Each narrow slit within the broad source can produce its own interference pattern. When combined, these patterns can overlap, leading to a situation where the distinct interference pattern is not visible. This supports the assertion that interference is not observed clearly.

### Step 3: Conclusion
Both the assertion and the reason are true. The reason provided correctly explains the assertion. Therefore, we conclude that:

- **Assertion**: True
- **Reason**: True
- **Relationship**: The reason is the correct explanation for the assertion.

### Final Answer
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.

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