NCIDQ Lighting Design 1 — Questions and Answers
Question 1: What is the standard unit of measurement for luminous flux, representing the total quantity of light emitted by a source?
- Lux
- Lumen (Correct answer)
- Candela
- Footcandle
Correct answer: Lumen
The lumen (lm) is the SI unit of luminous flux, measuring the total amount of visible light emitted by a source per unit of time.
Question 2: Which Color Rendering Index (CRI) value represents perfect color accuracy under a light source?
- 75
- 85
- 95
- 100 (Correct answer)
Correct answer: 100
A CRI of 100 is the maximum value, representing perfect color rendering comparable to natural daylight; higher values indicate more accurate color rendition.
Question 3: A color temperature of approximately 3000K would best be described as:
- Cool white
- Daylight
- Warm white (Correct answer)
- Neutral white
Correct answer: Warm white
3000K falls in the warm white range (2700–3200K), producing a yellowish-white light similar to halogen or incandescent lamps.
Question 4: Footcandles (fc) are used to measure which lighting quantity?
- Light output of a lamp
- Illuminance on a surface (Correct answer)
- Luminous intensity of a fixture
- Luminous efficacy of a system
Correct answer: Illuminance on a surface
Footcandles measure illuminance—the amount of light falling on a surface—where one footcandle equals one lumen per square foot.
Question 5: Which layer of the three-layer lighting approach is specifically intended to illuminate a task surface like a desk or countertop?
- Ambient lighting
- Task lighting (Correct answer)
- Accent lighting
- Decorative lighting
Correct answer: Task lighting
Task lighting provides concentrated, focused illumination directly on work surfaces to support specific visual activities like reading or food preparation.
Question 6: What is the definition of glare in interior lighting design?
- The total lumen output of all fixtures in a space
- The color shift of lamps as they age
- Excessive or uncontrolled brightness causing visual discomfort or reduced visibility (Correct answer)
- The reflection of light off polished floor surfaces
Correct answer: Excessive or uncontrolled brightness causing visual discomfort or reduced visibility
Glare is defined as excessive brightness within the visual field that causes discomfort, annoyance, or impaired visibility compared to the adapted luminance level.
Question 7: Which lamp technology offers the highest combination of energy efficiency and longest rated lifespan?
- Incandescent
- Halogen
- Compact fluorescent (CFL)
- LED (Correct answer)
Correct answer: LED
LED lamps provide the highest energy efficiency (lumens per watt) and longest lifespan—often 25,000–50,000+ hours—compared to all other common lamp types.
NCIDQ Lighting Design 1
What is the standard unit of measurement for luminous flux, representing the total quantity of light emitted by a source?