CLD Lighting Design Principles & Techniques 4

Question 1

What does the term 'efficacy' mean when applied to a light source?

Accepted Answer

The ratio of luminous flux output to electrical power input, expressed in lumens per watt

Answer

Efficacy measures energy efficiency: how many lumens a source produces for each watt of electricity consumed, expressed as lm/W.

Question 2

A designer wants to create visual hierarchy in a museum gallery. Which lighting ratio between accent and ambient levels is commonly recommended?

Accepted Answer

3:1 to 5:1 (accent three to five times brighter than ambient)

Answer

A 3:1 to 5:1 accent-to-ambient ratio creates clear focal emphasis on artwork while maintaining comfortable visibility throughout the space.

Question 3

What is the Kruithof curve used for in lighting design?

Accepted Answer

Identifying combinations of illuminance level and color temperature perceived as pleasant and natural

Answer

The Kruithof curve maps combinations of illuminance (lux) and CCT that human observers tend to find comfortable and pleasing versus unpleasant or unnatural.

Question 4

What is the primary design consideration when specifying luminaires for a space with a high ambient temperature, such as above a commercial kitchen hood?

Accepted Answer

Choosing luminaires rated for the elevated ambient temperature to ensure lamp life and safety

Answer

Luminaires must be rated (T-rating) for elevated ambient temperatures, as excessive heat degrades lamp output, shortens life, and can create fire hazards.

Question 5

In healthcare lighting design, why is flicker an especially critical concern?

Accepted Answer

Flicker can trigger photosensitive epilepsy and cause visual discomfort in patients and staff

Answer

In healthcare settings, flicker at certain frequencies can trigger seizures in photosensitive patients and cause headaches, eyestrain, and distraction for clinical staff.

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Lighting Design Principles & Techniques 4