A : When viewing through a compound microscope, our eyes should be positioned not on the eye piece but a short distance away from it for best viewing.
R : The image of the objective in the eye-piece is known as 'eye-ring' and if we position our eyes on the 'eye-ring' and the area of the pupil of out eye is greater or equal to the area of the eye ring, our eyes will collect all the light refracted by the objective.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4).

Answer

To analyze the given statements regarding the use of a compound microscope, we can break down the assertions and reasoning step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that when viewing through a compound microscope, our eyes should be positioned not directly on the eyepiece but at a short distance away for the best viewing experience.
- This is based on the principle of maximizing the light entering the eye and ensuring a clearer image.

2. **Understanding the Reason (R)**:
- The reason explains that the image formed by the objective lens in the eyepiece is known as the 'eye-ring'.
- If the eye is positioned correctly on the eye-ring, and the area of the pupil of the eye is equal to or greater than the area of the eye-ring, then the eye will collect all the light that has been refracted by the objective lens.

3. **Analyzing the Relationship Between A and R**:
- Both the assertion and the reason are correct. The assertion correctly describes the optimal positioning of the eye for best viewing through a microscope.
- The reason provides a valid explanation for why this positioning is necessary. If the eye is too close to the eyepiece, it may not capture all the light, leading to a less clear image.

4. **Conclusion**:
- Since both the assertion and the reason are true, and the reason correctly explains the assertion, we can conclude that the statements are valid.

### Final Answer:
Both the assertion (A) and the reason (R) are correct, and the reason (R) provides a valid explanation for the assertion (A).

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