(A): Sound produced by an open organ pipe is richer than the sound produced by a closed organ pipe.
(R): Outside air can enter the pipe from both ends, in case of open organ pipe.

Options

A. Both 'A' and 'R' are true and 'R' is the correct, explanation of 'A'.
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. A' is true and 'R' is false
D. Both 'A' and 'R' are false

Answer

To analyze the given statements and determine their truthfulness and relationship, we can follow these steps:

### Step 1: Understand the Assertion
The assertion (A) states that "Sound produced by an open organ pipe is richer than the sound produced by a closed organ pipe."

- **Explanation**: An open organ pipe allows sound waves to resonate in a way that produces a richer sound because it can produce a wider range of harmonics. This is due to the fact that open pipes support both even and odd harmonics.

### Step 2: Understand the Reason
The reason (R) states that "Outside air can enter the pipe from both ends, in case of open organ pipe."

- **Explanation**: This statement is true as well. An open organ pipe has openings at both ends, allowing air to move freely in and out, which contributes to the sound production. However, this fact alone does not explain why the sound is richer.

### Step 3: Analyze the Relationship between A and R
Now we need to determine if R correctly explains A.

- While both A and R are true, the reason provided (R) does not adequately explain why the sound from an open organ pipe is richer than that from a closed organ pipe. The richness of the sound is primarily due to the harmonic content, not merely the ability of air to enter from both ends.

### Conclusion
Based on the analysis:
- Both A and R are true.
- R does not serve as a correct explanation for A.

Thus, the correct answer is: **Both A and R are true, but R is not the correct explanation of A.**