### Correct Option: B. To magnify images by converging light rays ### Detailed Explanation: A convex lens, also known as a converging lens, is a transparent optical device that is thicker in the center than at the edges. Its primary function is to bend (refract) light rays that pass through it in such a way that they converge to a point. This property is what allows convex lenses to magnify images. #### How Convex Lenses Work: 1. **Refraction of Light**: When light rays enter a convex lens, they slow down and change direction due to the lens material (usually glass or plastic) being denser than air. This bending of light is called refraction. 2. **Focal Point**: The point where the refracted rays converge is called the focal point. The distance from the center of the lens to the focal point is known as the focal length. For a convex lens, parallel rays of light that enter the lens converge at this focal point. 3. **Image Formation**: Depending on the position of the object relative to the lens, different types of images can be formed: - If the object is placed beyond the focal point, a real and inverted image is formed on the opposite side of the lens. - If the object is placed between the focal point and the lens, a virtual and upright image is formed on the same side as the object, which can be magnified. 4. **Magnification**: The ability of a convex lens to magnify images is crucial in various optical instruments such as magnifying glasses, cameras, and microscopes. The magnification (M) can be calculated using the formula: \[ M = \frac{h'}{h} = \frac{v}{u} \] where: - \( h' \) = height of the image - \( h \) = height of the object - \( v \) = image distance from the lens - \( u \) = object distance from the lens ### Why Other Options Are Incorrect: - **Option A: To disperse light into its component colors** This option describes the function of a prism, not a convex lens. While a convex lens can cause some chromatic aberration (where different colors focus at different points), its primary function is not to disperse light but to converge it. - **Option C: To block light from passing through** This statement is incorrect because a convex lens is designed to allow light to pass through and refract it, not block it. Blocking light is a function of opaque materials, not transparent lenses. - **Option D: To reflect light away from the lens surface** Convex lenses do not reflect light; they refract it. Reflection is a property of mirrors, not lenses. While some light may be reflected at the surface of the lens, the primary function of a convex lens is to refract and converge light. ### Common Pitfalls: - **Confusing Lenses with Mirrors**: Remember that lenses refract light while mirrors reflect it. This is a common source of confusion. - **Misunderstanding Image Types**: Be clear about the differences between real and virtual images. Real images can be projected onto a screen, while virtual images cannot. - **Ignoring Focal Length**: The position of the object relative to the focal length is crucial in determining the type of image formed. Always consider where the object is placed concerning the lens. ### Revision Summary: - A convex lens converges light rays to magnify images. - It has a focal point where light rays meet after refraction. - The lens can form both real and virtual images depending on the object's position. - Key formulas for magnification involve the heights and distances of the object and image.