Certified Paraoptometric (CPO) Practice Exam 2025

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Prepare for the Certified Paraoptometric Exam with our comprehensive quiz featuring multiple-choice questions. Each question is accompanied by hints and explanations, helping you build your knowledge and confidence. Get ready to excel in your career!

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What type of lens is used to diverge parallel light?

Convex
Concave
Spherical
Planar

The correct answer is: Concave

The correct choice is the concave lens. A concave lens is designed to diverge parallel light rays that enter it. When parallel light rays pass through a concave lens, they are refracted outward, spreading apart. This characteristic makes concave lenses useful in various applications, such as in eyeglasses for nearsightedness and in optical devices like cameras and microscopes. In contrast, a convex lens converges light rays to a focal point rather than diverging them, making it the opposite of what is being asked in the question. Spherical refers to the shape of the lens rather than its function regarding light rays, and planar indicates a flat surface rather than a lens type that would diverge light. Thus, the unique function of concave lenses to diverge light confirms its correctness in this context.