Final answer:
A lens is a material that refracts or bends light, allowing the formation of images in various optical devices.
Step-by-step explanation:
A lens is a material that refracts or bends light. When light passes through a lens, it changes direction due to the varying density of the material. This bending of light allows lenses to form images and is the basis for many optical devices, such as eyeglasses and microscopes. Mirrors, on the other hand, reflect light rather than refracting it, while magnets have no impact on the refraction of light.
Learn more about Refraction of Light