Physics help from experts.
See also solar landscape lighting fixtures
Lighting refers to illumination or the state of being lit. It also means the process of igniting. Lighting can mean the fixtures used to provide artificial illumination or to the process of such illumination.
Landscape lighting fixtures are used to accent or provide safety and security to scenery or architecture, or other structures such as bridges.
A lighting fixture is an electrical device used to provide artificial illumination. It may also refer more specifically to the receptacle that holds the bulb or tube.
Incandescent means having the property of emitting visible light when heated; the adjective form of incandescence.
This diagram shows a simplified view of the incandescent bulb. The main operating feature is the filament (thin wire) that heats up and glows when electric current flows through it. One end of the filament is attached to an electrode, the other to the base which screws into the receptacle (socket). The base and electrode are separated by insulating material so that they do not form a short circuit. The insulating material also forms the base of the support structures.
The entire unit is air tight to keep oxygen out. This extends the life of the filament.
The problem with most incandescent bulbs is that most of the electrical energy (as much as 95%) is used to produced heat, not light.
Having the property of fluorescence; adjective form of fluorescence.
Fluorescence is giving off light (particularly visible light) of one wavelength immediately after absorbing energy of a different wavelength.
When an atom absorbs a packet of energy, one of its electrons is bumped up to a higher energy level. The electron may shortly thereafter "fall" down to a lower energy level, but not necessarily to the original energy level it was in. When the electron moves to the lower energy level, it gives off light.
Fluorescent tubes are constructed of glass coated on the inside with a phosphor. Inside the tube is a low-pressure mixture of mercury and argon. At both ends of the tube is an electrode coated with a material that gives off electrons when heated (thermionic emission).
When electric current flows through the electrodes, electrons are given off which energize the mercury. The mercury in turns gives off ultraviolet light. The ultraviolet light strikes the phosphor coating on the glass, which in turn gives off visible light.
Although this is a complex process, very little energy is given off as heat. Since most of the energy given off is light, fluorescent tubes are more economical to operate for long periods than are most incandescent bulbs.
Thermionic emission is the flow of electrons from a metal or metallic oxide surface caused by heating the material so that the surface electrons have enough energy to overcome the electrical forces holding the electrons to the material.
Some people believe the fluorescent lamp was invented by and named after a famous Filipino physicist, Agapito Flores. However Flores was born in Guiguinto, Bulacan, Philippines on September 28, 1897, and an American, Peter Cooper Hewitt patented the mercury vapor lamp in 1901.