Politically, Ireland is divided between the Republic of Ireland (officially also named Ireland), which covers five-sixths of the island, and Northern Ireland, a part of the United Kingdom, which covers the remaining area and is located in the northeast of the island.orthern Ireland is a part of the United Kingdom with a local executive and assembly which exercise devolved powers. The executive is jointly headed by the first and deputy-first minister, with the ministries being allocated in proportion with each party's representation in the assembly. Its capital is Belfast.
Lens (optics) For other uses, see Lens. A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis.
A transparent structure behind the iris of the eye that focuses light entering the eye on the retina. A piece of glass or plastic shaped so as to focus or spread light rays that pass through it, often for the purpose of forming an image. A combination of two or more such lenses, as in a camera or telescope. Also called compound lens. A device that causes radiation to converge or diverge by an action analogous to that of an optical lens. The system of electric fields used to focus electron beams in electron microscopes is an example of a lens.