As a plus lens is moved closer to the eye, it becomes ________.

As a plus lens is moved closer to the eye, it becomes less effective because the lens creates a specific focal length at which light rays converge to form a clear image. When a plus lens is positioned further away from the eye, it allows the lens to project light rays that eventually converge at a point behind the lens, which corresponds to a clear vision for specific distances. However, as the lens is brought closer, the focal point shifts forward, and the light rays diverge differently, causing the image to become less clear and less effective for vision. This change in the effective focal point diminishes the lens's ability to magnify or clarify the viewed object, leading to the situation described.

In contrast, the other options do not accurately describe the behavior of plus lenses as their distance from the eye changes.