Free CLC Practice Questions

Question 1

An empty kitchen counter measures 540 lx, exceeding the project's 500 lx task target. When someone stands in the normal food-preparation position, their body blocks the ceiling downlights and the cutting area becomes dark. The ceiling locations and cabinetry must remain. Which revision addresses the cause rather than simply increasing room brightness?

Accepted Answer

Add shielded undercabinet lighting near the cabinet fronts, directed onto the preparation area.

Answer

Replace the ceiling lamps with higher-output versions while keeping their present positions and aiming.

Answer

Install indirect lighting above the upper cabinets to raise the brightness of the ceiling.

Answer

Add a linear source at the rear of each upper cabinet, aimed toward the backsplash.

Question 2

At a kitchen mock-up, a client approves the 2700 K appearance and the amount of light but finds red foods and finishes dull. The installed source has general CRI Ra 91 and R9 20. The replacement must retain 2700 K and Ra of at least 90. With output, optics, and compatibility otherwise equal, which specification best addresses the color-rendering weakness?

Accepted Answer

2700 K; Ra 92; R9 85.

Answer

2700 K; Ra 94; R9 40.

Answer

4000 K; Ra 95; R9 90.

Answer

2200 K; Ra 93; R9 80.

Question 3

A reflected ceiling plan places recessed downlights on 8 ft centers. The section shows the luminous apertures 11 ft above the finished floor and the workplane 3 ft above the floor. The manufacturer gives a spacing criterion of 1.1 in the direction being checked. Before the point-by-point analysis, which note correctly applies the spacing criterion?

Accepted Answer

Maximum spacing is 8.8 ft; retain the proposed 8 ft centers.

Answer

Maximum spacing is 3.3 ft; reduce the proposed 8 ft centers.

Answer

Maximum spacing is 7.3 ft; reduce the proposed 8 ft centers.

Answer

Maximum spacing is 12.1 ft; retain the proposed 8 ft centers.

Question 4

Six LED downlights flicker only when dimmed below 8% output. The electrician confirms correct wiring, an approved dimmer-driver pairing, and a load within the permitted range. The manufacturer specifies stable operation from 10% to 100% and permits low-end trim adjustment. The client's lowest required scene is 15%. How should this behavior be addressed?

Accepted Answer

Set low-end trim for 12% light output; verify stable dimming and startup in the 15% scene.

Answer

Keep the zone out of service and replace all six drivers because low-level flicker establishes a hardware defect.

Answer

Add another lamp to increase the connected load before making any adjustment to the dimmer's operating range.

Answer

Reduce the high-end trim to limit the maximum current, leaving the lowest selectable output unchanged.

Question 5

For a glare review, a consultant needs to compare a pendant's luminous shade with the adjacent wall from the client's seated viewing position. The reading surface already has adequate illuminance. Which measurement captures the surface-to-surface difference relevant to this review?

Accepted Answer

Luminance in cd/m², measured toward each surface from the seated viewing position.

Answer

Illuminance in lux, measured with a detector facing upward on the reading surface.

Answer

Total luminous flux in lumens, measured with the pendant inside an integrating sphere.

Answer

Correlated color temperature in kelvin, measured for the light arriving at the sofa.

Question 6

A bathroom vanity is lit by one recessed downlight directly above the user's head. The countertop is bright, but grooming is difficult because the eye sockets and the area beneath the chin remain in shadow. The client is satisfied with the source's color quality. What change would most directly improve facial modeling?

Accepted Answer

Place broad, diffused vertical light sources to the left and right of the mirror at face height.

Answer

Increase the output of the existing overhead downlight while retaining its location and optic.

Answer

Add a concealed source below the mirror, directing most of its light upward onto the face.

Answer

Replace the overhead downlight with a narrower beam centered on the user's standing position.

Question 7

During an on-site lighting test, a burning-insulation odor develops at a recessed driver's enclosure. The lights remain on and the circuit breaker has not tripped. There is no visible smoke or flame, and the project's electrician is present. What takes priority over completing the aiming adjustments?

Accepted Answer

Stop the test and keep people clear while the electrician isolates the affected circuit before inspection.

Answer

Reduce the dimming level and continue briefly to determine whether lower output makes the odor disappear.

Answer

Switch the lamps off at the dimmer and open the enclosure without interrupting the branch-circuit supply.

Answer

Check whether the connected wattage is below the breaker rating and continue if that rating is not exceeded.

Question 8

An LED luminaire submittal quotes L70 at 60,000 hours, based on LED-source LM-80 data and a TM-21 projection. The driver has a separate five-year warranty. A client wants to use the 60,000-hour figure for maintenance planning. What does that figure actually support?

Accepted Answer

A 70% LED-source lumen-maintenance projection under its stated conditions, not a complete-luminaire survival or warranty claim.

Answer

The complete luminaire's operating life before any optical or electrical component is expected to need service.

Answer

The operating time at which 70% of the original luminaires are expected to remain functional.

Answer

The minimum operating life covered by the manufacturer, independently of the driver's five-year warranty.

Question 9

A shower-light substitution must fit the coordinated ceiling section's 3 in maximum installation depth. The light is exposed to direct shower spray and must work with the scheduled reverse-phase dimmer. All four candidates have confirmed insulation-contact suitability and meet the specified output and color requirements. Their manufacturers confirm the ratings shown. Which submittal fits without changing the ceiling or controls?

Accepted Answer

2.5 in installation depth; wet-location ceiling use; compatible with the scheduled reverse-phase dimmer.

Answer

4.5 in installation depth; wet-location ceiling use; compatible with the scheduled reverse-phase dimmer.

Answer

2 in installation depth; damp-location ceiling use only; compatible with the scheduled reverse-phase dimmer.

Answer

2 in installation depth; wet-location ceiling use; compatible with forward-phase dimming only.

Question 10

A 77-year-old reader says, 'The page is clear, but when I look up, I struggle to see anything else.' A shielded task lamp provides comfortable reading light; the surrounding room is almost dark. Lowering the task output makes the print harder to read. Which adjustment best balances these needs?

Accepted Answer

Introduce modest indirect ambient lighting and keep the task lamp independently adjustable at the comfortable reading level.

Answer

Increase task-lamp output further without altering the existing background illumination.

Answer

Change to a higher-CCT task lamp without altering the surrounding illumination.

Answer

Reduce spill from the task lamp so the reader can remain dark-adapted between glances at the page.

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