What characteristic defines an achromatic lens?

What characteristic defines an achromatic lens?

• A. It focuses all colors of light equally
• B. It eliminates spherical aberration
• C. It reduces chromatic aberration
• D. It produces monochromatic light

Answer: (C)

An achromatic lens is specifically designed to reduce chromatic aberration, which is the failure of a lens to focus all colors of light at the same point. Chromatic aberration occurs because different wavelengths (colors) of light refract at different angles when passing through a lens material. An achromatic lens typically consists of two different types of glass with different refractive indices, often combining one convex and one concave lens. This construction enables the lens to correct for the dispersion of colors, allowing it to bring two wavelengths of light, usually red and blue, to a common focus, thus significantly improving image quality. The other options touch on different concepts related to lens properties and optical performance. While focusing all colors equally relates to chromatic aberration, it is not the defining characteristic of an achromatic lens, as it does not focus all colors perfectly. Eliminating spherical aberration is a different optical issue and is not the primary goal of an achromatic design. Producing monochromatic light pertains to light sources and filters and does not directly relate to the definition or purpose of an achromatic lens. The focus on reducing chromatic aberration is what clearly delineates an achromatic lens from other optical components.

An achromatic lens is specifically designed to reduce chromatic aberration, which is the failure of a lens to focus all colors of light at the same point. Chromatic aberration occurs because different wavelengths (colors) of light refract at different angles when passing through a lens material. An achromatic lens typically consists of two different types of glass with different refractive indices, often combining one convex and one concave lens. This construction enables the lens to correct for the dispersion of colors, allowing it to bring two wavelengths of light, usually red and blue, to a common focus, thus significantly improving image quality.

The other options touch on different concepts related to lens properties and optical performance. While focusing all colors equally relates to chromatic aberration, it is not the defining characteristic of an achromatic lens, as it does not focus all colors perfectly. Eliminating spherical aberration is a different optical issue and is not the primary goal of an achromatic design. Producing monochromatic light pertains to light sources and filters and does not directly relate to the definition or purpose of an achromatic lens. The focus on reducing chromatic aberration is what clearly delineates an achromatic lens from other optical components.