How can a plus lens be simplistically described?

A plus lens, often referred to as a converging lens, can be simplistically described as two prisms base to base. This description highlights the way light behaves when passing through a plus lens.

In a plus lens, the edges are thinner than the center, allowing it to converge light rays that are coming in parallel (such as rays from a distant object). When you visualize the lens as two prisms placed with their bases touching, it becomes clear how the lens bends light inward toward the optical axis. This inward bending of light rays causes them to focus at a point, forming a clear image for the viewer.

The other options do not accurately describe the nature of a plus lens. Viewing it as two prisms apex to apex would suggest a configuration that diverges light rather than converges it. Similarly, characterizing a plus lens as flat with minor curvature does not capture the essential functionality of a converging lens, which is defined by its parabolic shape to effectively gather light. Lastly, describing it as one solid piece of glass omits the crucial aspect of how its curvature influences the path of light.

Understanding a plus lens in this manner helps to reinforce why it is effective in applications such as magnifying glasses or as part of