The correct option for the type of lens used to correct nearsightedness (myopia) is **B. Concave lens**. ### Detailed Explanation 1. **Understanding Myopia**: - Myopia, or nearsightedness, is a common vision condition where distant objects appear blurry while close objects can be seen clearly. This occurs because the eye is either too long or the cornea has too much curvature, causing light rays to focus in front of the retina instead of directly on it. 2. **Role of Lenses**: - Lenses are used to correct vision by altering the path of light rays entering the eye. The goal is to ensure that light rays focus directly on the retina. 3. **Concave Lens Functionality**: - A concave lens is thinner at the center than at the edges and has a negative focal length. When parallel light rays (from distant objects) pass through a concave lens, they diverge (spread out) after passing through the lens. This divergence allows the light rays to extend backward, effectively moving the focal point further back, so that it aligns with the retina. - In simpler terms, the concave lens helps to "pull" the focus back onto the retina, allowing the person to see distant objects more clearly. 4. **Why Other Options Are Incorrect**: - **A. Convex lens**: A convex lens is thicker in the center and causes light rays to converge (come together). This type of lens is used to correct farsightedness (hyperopia), where distant objects are seen clearly, but close objects are blurry. Therefore, it does not help with myopia. - **C. Plano-convex lens**: This lens has one flat surface and one convex surface. While it can converge light, it is not specifically designed for correcting myopia. It is more commonly used in applications like magnifying glasses or certain optical instruments. - **D. Biconvex lens**: Similar to the convex lens, a biconvex lens is thicker in the center and also converges light rays. Like the plano-convex lens, it is not suitable for correcting myopia. ### Summary of Key Points - **Myopia** is a condition where distant objects appear blurry due to improper light focus. - **Concave lenses** diverge light rays, allowing them to focus correctly on the retina for nearsighted individuals. - **Convex, plano-convex, and biconvex lenses** are used for correcting farsightedness and are not suitable for myopia. ### Revision Summary - Myopia (nearsightedness) causes distant objects to appear blurry. - A **concave lens** diverges light rays, correcting myopia by moving the focus back onto the retina. - Convex lenses are used for farsightedness, not myopia. - Understanding lens shapes and their effects on light is crucial for correcting vision problems.