Refracts parallel rays of light inward towards a focal point.
Explanation
A lens is a transparent optical medium bounded by two surfaces, at least one of which is spherical. Lenses function based on the principle of refraction, which is the bending of light as it passes from one medium to another. A convex lens is characterized by being thicker at the center than at the edges.
Detailed Analysis:
- Diverges parallel rays of light outward. is incorrect: Diverging parallel rays of light outward is the property of a concave lens. A concave lens is thinner at the center and causes light rays to spread apart.
- Refracts parallel rays of light inward towards a focal point. is correct: When a beam of light rays parallel to the principal axis passes through a convex lens, the rays are refracted inwards. They meet (converge) at a specific point on the principal axis called the principal focus. Due to this specific action of bringing parallel rays together, a convex lens is technically termed a "converging lens."
- Reflects light back to the source. is incorrect: Reflection of light back to the source is the property of a mirror, not a lens. Lenses transmit and refract light, whereas mirrors reflect it.
- Disperses white light into its spectrum. is incorrect: While lenses can cause dispersion (chromatic aberration), the primary definition of a "converging lens" relates to the geometric path of light rays (convergence) rather than the separation of wavelengths (dispersion). Dispersion is the primary function of a prism.
Key Takeaway:
A convex lens refracts parallel light rays inward to converge at a focal point, whereas a concave lens refracts light rays outward, causing them to diverge.