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CLC Photometry & Color Science Flashcards

6 cards from real CLC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 CLC Photometry & Color Science flashcards as text

  1. The Coefficient of Utilization (CU) in the zonal cavity method accounts for which two factors?

    Answer: Luminaire efficiency and room surface reflectances

    CU combines the luminaire's efficiency with the room's cavity reflectances (ceiling, wall, floor) to predict the fraction of emitted lumens reaching the work plane.

  2. The R9 value within the extended CRI test is specifically used to evaluate a source's ability to render which color?

    Answer: Saturated red

    R9 measures rendering accuracy for saturated red, which is critical for applications like retail, hospitality, and healthcare where red tones matter.

  3. Glare is most commonly quantified in interior commercial spaces using which metric?

    Answer: Unified Glare Rating (UGR)

    The Unified Glare Rating (UGR) is the internationally adopted metric for assessing discomfort glare in interior lighting, specified in IES and CIE standards.

  4. Spectroradiometry differs from photometry in that it measures light weighted by which function?

    Answer: The actual radiometric power at each wavelength without eye weighting

    Spectroradiometry measures absolute radiant power at each wavelength without applying the eye's sensitivity weighting, unlike photometry which uses V(λ).

  5. Which term describes the ratio of maintained horizontal illuminance to minimum horizontal illuminance across a defined area?

    Answer: Illuminance uniformity ratio

    The illuminance uniformity ratio (average-to-minimum) confirms that light is distributed evenly enough to prevent dark spots in the work area.

  6. In the IES zonal cavity calculation method, the Room Cavity Ratio (RCR) is calculated using room length, width, and which other dimension?

    Answer: Cavity height (distance from luminaire plane to work plane)

    RCR = 5 × cavity height × (length + width) / (length × width), using the vertical distance between the luminaire mounting plane and the work plane.