How does a lens focus light?

• A. By reflecting light rays away from a focal point.
• B. By absorbing light rays.
• C. By refracting light rays towards a focal point.
• D. By scattering light in multiple directions.

Answer: (C)

A lens focuses light by refracting light rays towards a focal point. When light passes through a lens, the shape of the lens causes it to bend, or refract, the incoming light rays. This bending occurs because light travels at different speeds in different materials, such as air and glass.

For a converging lens, which is thicker in the middle and thinner at the edges, parallel light rays entering the lens are bent inward and converge at a specific point known as the focal point. The degree of bending depends on the curvature of the lens and the refractive index of the material from which it is made.

This phenomenon is essential in many optical devices, including glasses, cameras, and microscopes, where precise focus is necessary to produce clear images. The ability of a lens to change the direction of light ensures that images can be formed at various distances from the lens as light rays are redirected to meet at a common point.

Other options involve processes that do not lead to focusing light correctly. For example, reflecting light away from a focal point or absorbing it would prevent the convergence necessary for focusing. Similarly, scattering light in multiple directions does not contribute to focusing but instead disperses the light.