Lighting Flashcards
What is the visible light spectrum span?
350nm to 750nm
What is Luminous intensity?
This is the power of the light source to emit light flux in a particular direction
What is the unit used to measure luminous intensity?
candela (cd) pronounced “can dee la”
What is candela (cd) used to measure?
Luminous intensity
What is the symbol for candela?
ɪ
What does the symbol “ ɪ “ represent?
Candela, for luminous intensity.
What is luminous flux?
Luminous flux is the rate of flow of light energy from a source.
What is the unit for luminous flux?
Lumen (lm)
What is does unit lumen (lm) represent?
Luminous flux
What is the symbol for luminous flux?
Φ of F.
What does the symbols Φ and F represent in lighting?
Luminous flux
What is illuminance?
Illuminance is the amount of light energy reaching a surface.
What is the unit for illuminance?
The unit for illuminance is Lux (lx) or Lm/m2 and its symbol is E
How do you calculate illuminance?
Illuminance = Luminous flux
————
area
Or
E = F (Φ)
——
A
What illuminance level is emergency lighting rated at?
A minimum of 0.2 lux
What illuminance level is bright sunlight rated at?
Approximately 50,000 Lux.
What is the difference between luminous flux and illuminance?
Illuminance measured the light at the surface whereas luminous flux measures the flow of light from the source.
What does GLS stand for?
General Lighting Service
Describe the term colour rendering
Colour rendering is the ability to make a light more or less natural depending on the usage.
What is the operating position of a GLS lamp
Any position
What is the operating position of a tungsten halogen lamp?
Low voltage lamps can go in any position but linear lamps should be places in a horizontal position
