The correct option is **B. It diverges light rays, causing them to spread out.** ### Detailed Explanation: 1. **Understanding Concave Lenses:** - A concave lens is a type of lens that is thinner in the center than at the edges. This shape causes light rays that pass through the lens to diverge, or spread out, rather than converge to a point. 2. **How Concave Lenses Work:** - When parallel light rays (like those from a distant object) enter a concave lens, they are refracted (bent) outward. The lens causes the rays to diverge as if they are emanating from a single point called the "virtual focal point," which is located on the same side of the lens as the incoming light. - The focal point of a concave lens is virtual because the light rays do not actually meet at this point; they only appear to come from it when traced backward. 3. **Image Formation:** - Concave lenses typically produce virtual images that are upright and smaller than the object. This is useful in various optical devices, such as eyeglasses for nearsightedness, where the lens helps to correct the vision by diverging light rays before they reach the eye. ### Why Other Options Are Incorrect: - **Option A: It converges light rays to a focal point.** - This statement describes the function of a **convex lens**, not a concave lens. Convex lenses are thicker in the center and cause parallel light rays to converge to a focal point on the opposite side of the lens. - **Option C: It magnifies distant objects.** - While concave lenses can magnify images, they do not do so for distant objects. Instead, they are more effective for nearby objects. The magnification effect is not the primary function of a concave lens; rather, it is the divergence of light rays that is key. - **Option D: It focuses light to produce a virtual image.** - This statement is misleading. A concave lens does not focus light in the traditional sense; it diverges light. The term "focus" implies that light converges at a point, which is not the case with concave lenses. They produce virtual images, but the light does not focus to create these images. ### Formulas and Diagrams: - The lens formula for thin lenses is given by: \[ \frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i} \] where: - \( f \) = focal length (negative for concave lenses) - \( d_o \) = object distance (positive for real objects) - \( d_i \) = image distance (negative for virtual images) - **Diagram Description:** - Imagine a concave lens in the center of a diagram. Light rays from a distant object approach the lens parallel to its principal axis. After passing through the lens, these rays diverge outward. If you trace these rays backward, they appear to originate from a point on the same side of the lens as the object, which is the virtual focal point. ### Common Pitfalls: - Confusing concave lenses with convex lenses is a common mistake. Remember that concave lenses diverge light, while convex lenses converge it. - Misunderstanding the nature of virtual images can lead to confusion. Virtual images cannot be projected onto a screen, as they do not actually exist at a physical location. ### Revision Summary: - Concave lenses diverge light rays, causing them to spread out. - They produce virtual images that are upright and smaller than the object. - The focal length of a concave lens is negative, indicating that the focal point is virtual. - Remember the lens formula and the distinction between concave and convex lenses to avoid common mistakes.