What does a lens in optics primarily do?

A lens in optics primarily focuses light by bending (refracting) incoming rays. When light passes through a lens, the curved surfaces cause the light rays to converge or diverge depending on the shape of the lens—convex lenses focus light to a point, while concave lenses spread light rays out. This focusing property allows lenses to form images, which is fundamental in applications like cameras, microscopes, and glasses.

In contrast, reflecting light pertains to mirrors rather than lenses, while absorbing energy is not the primary function of lenses, as they are designed to transmit light rather than absorb it. Scattering sound is unrelated to optics and the function of lenses, as this pertains more to acoustics. Understanding the critical role of lenses in focusing light highlights their importance in various optical devices and scientific applications.