When objects at different distances are seen by the eye, which of the following remain constant?

Options

A. the focal length of the eye lens
B. the object distance from the eye lens
C. the radii foc curavature of the eye lens
D. the image distance from the the eye lens

Answer

To solve the question of which parameters remain constant when objects at different distances are seen by the eye, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Eye's Structure**: The human eye consists of various parts, including the cornea, lens, and retina. The retina is the part of the eye where the image is formed.

2. **Image Formation**: When light from an object enters the eye, it passes through the cornea and lens, which focus the light onto the retina. The retina is located at a fixed distance from the lens.

3. **Fixed Image Distance**: Regardless of the distance of the object being viewed, the image formed by the eye is always projected onto the retina. This means that the distance from the lens to the retina remains constant.

4. **Conclusion**: The constant factor when viewing objects at different distances is the image distance from the lens to the retina. Thus, the image distance remains constant.

### Final Answer:
When objects at different distances are seen by the eye, the image distance from the lens to the retina remains constant.

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