
232 Glossary
Hot Restart Time: The time it takes for a high-intensity discharge lamp to reach 90% of
light output after going from on to off to on.
Illuminance: The density of light (lumens/area) incident on a surface; that is, the light
level on a surface. Illuminance is measured in footcandles or lux.
Incandescent Lamp: A light source that generates light utilizing a thin lament wire
(usually of tungsten) heated to white by an electric current passing through it.
Induction Lighting: Gases can be excited directly by radiofrequency or microwaves from
a coil that creates induced electromagnetic elds. This is called induction light-
ing and it ...