Practice Test Geeks(CLC) Certified Lighting Consultant Practice Test
← All CLC Flashcard Decks

Light Source Technology & LEDs Flashcards

7 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 7 Light Source Technology & LEDs flashcards as text

  1. Which color rendering metric was developed specifically to address CRI's weakness in evaluating LED sources with narrow spectral peaks?

    Answer: TM-30-20 Rf and Rg

    IES TM-30-20 introduced Rf (fidelity) and Rg (gamut) indices using 99 color evaluation samples, providing a more complete picture of LED color rendering than CRI.

  2. What is 'photobiological safety' in the context of LED luminaires as defined by IEC 62471?

    Answer: An evaluation of optical radiation hazards including blue light, UV, and IR to eyes and skin

    IEC 62471 classifies lamps and luminaires into risk groups (exempt through RG3) based on potential harm from UV, visible, and IR radiation to the eye and skin.

  3. When specifying LED luminaires for a museum application, which combination of metrics is MOST critical?

    Answer: High CRI (≥95), low R9 loss, and low UV output

    Museum lighting demands accurate color rendering (CRI ≥95, strong R9) and minimal UV radiation to protect artifacts from photodegradation.

  4. IES LM-79 is a photometric testing standard that requires LED luminaires to be tested at:

    Answer: 25°C ambient in a temperature-controlled integrating sphere or goniophotometer

    LM-79 specifies testing complete LED luminaires (not bare LEDs) at 25°C stabilized ambient temperature to ensure reproducible photometric data.

  5. What does the ANSI/IES TM-21 standard project?

    Answer: Long-term lumen maintenance beyond the tested hours using LM-80 data

    TM-21 provides a calculation method to extrapolate LED lumen maintenance life (e.g., L70) beyond the 6,000-hour LM-80 test period using mathematical modeling.

  6. Which factor most directly determines whether an LED luminaire qualifies as 'flicker-free' per WELL Building Standard criteria?

    Answer: Percent flicker below 5% and flicker index below 0.1 at all dimming levels

    WELL requires percent flicker ≤5% and flicker index ≤0.1 across all operating conditions to minimize stroboscopic effects and health concerns.

  7. In a tunable white LED system, two LED channels are typically used. What are they?

    Answer: A warm white (2700K) channel and a cool white (5000K–6500K) channel

    Tunable white luminaires blend a warm white CCT channel with a cool white CCT channel in variable ratios to achieve any intermediate color temperature.