What is the primary function of a lens?

The primary function of a lens is to refract and focus light. A lens is an optical device typically made of glass or transparent plastic that has the ability to bend light rays as they pass through it. This bending of light, known as refraction, occurs due to the change in speed of light when it moves between different media, such as air and the material of the lens.

By manipulating the path of light, lenses can converge (focus) light to form images or disperse it to produce different visual effects. This property makes lenses essential for a range of applications, including in cameras, eyeglasses, microscopes, and telescopes, allowing them to capture images or aid in magnifying objects.

Other options, such as absorbing light, creating shadows, or illuminating dark areas, do not capture the defining characteristic of a lens. While some materials can absorb light or create shadows, a lens's role is specifically tied to its ability to refract and focus light for various practical uses, making the chosen answer the most accurate representation of a lens’s primary function.