NCIDQ | LIGHTING QUESTIONS AND
ANSWERS WITH SOLUTIONS 2024
Lamp - ANSWER The correct term for the manufactured unit that produces light is a LAMP.
Do not confuse it with FIXTURE.
common lamps - ANSWER Incandescent
Halogen
Fluorescent
CFL or Compact Fluorescent Lamp
Metal Halide
High Pressure Sodium
Specialty
CRI - ANSWER Color Rendering
A measure of lighting quality.
This measure is based on an index that ranges from 1-100 with natural daylight and halogen lighting
being 100 CRI
Objects (such as artwork,
jewelry, fabrics) illuminated with halogen lamps that have a high CRI, will appear more true to life.
Color of objects can be perceived more accurately under lamps with a high CRI. Another wonderful
side effect of high CRI light sources is that they produce a higher perceived level of light (they look
brighter) which in turn makes them more energy effective (you save money).
Color Rendering Of Common Lamps - ANSWER Incandescent 100%
,Halogen 100%
Fluorescent 60% up to 92%
Metal Halide 65% up to 92%
High Pressure Sodium 21% up to 85%
Color Temperature - ANSWER is a measure of the apparent color of the light source (color appearance).
It is expressed
in Kelvin; the lower the color temperature, the warmer the apparent color, and the higher the color
temperature, the cooler the apparent color.
(a 2800K source will be warmer than a 600K
source.)
Light Source + Color Temperature - ANSWER Clear blue sky 12,000
Overcast sky 7,000
Sunlight 5,000
Metal Halide 4,500
Solux 3,500 to 4,700
Halogen 3,000
House Lamp 2,500
Candle Flame 1,500
Consider and compare the following when making an informed choice of lamp
type: - ANSWER Cost
Life
Wattage
Output (candela, candle power, or lumens)
CRI
,Color temperature
Ambient lighting - ANSWER general, overall illumination that:
• Enables one to move about easily and safely
• Defines the space
• Makes the room seem larger
• Makes the space more comfortable by balancing the brightness of surfaces and objects in the field of
view.
General lighting that brightens objects and surfaces in the lower part of the room creates a feeling of
warmth and intimacy, whereas indirect lighting, directed to the upper walls and ceiling, gives the space a
cooler, quieter, more spacious look.
Task Lighting - ANSWER light to work by
Task lighting illuminates areas where work is performed
Paper work and reading generally require plentiful, well-diffused light coming from
over the shoulder or from the side. For kitchen and hobby tasks, a concentrated light from above usually
works best.
Efficacy - ANSWER is a measure of efficiency, expressed in lumens per watt.
Visible light - ANSWER Form of electromagnetic radiation with wavelengths that range from abbout
400nm for violet light to about 700 nm for red light. White light is produced when source emits equal
quantities of energy over entire visible spectrum
Candlepower (CP) - ANSWER Unit of luminous intensity approximately equal to the horizontal light
output from an ordinary wax candle
Candela (CD) - ANSWER SI (metric) equivalent to Candlepower - unit of luminous intensity approximately
equal to the horizontal light output from an ordinary wax candle
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