Luminous flux of luminarie (Light fitting or bulb) Luminous flux is total light output emitted by luminarie. It is denoted by  (Φ) or lumen or lm. Light emitted by a light fitting, Lumen decreases with the distance from that light fitting. Illuminance(Lux) Illuminance or Lux is light density means light falling on a sq.meter surface … Continue reading Terms related to Lighting and Lighting fixtures ..