CLD Photometry & Light Measurement 3

Question 1

The Light Loss Factor (LLF) in a lighting calculation accounts for:

Accepted Answer

Reduction in illuminance over time due to lamp depreciation and dirt accumulation

Answer

LLF is a multiplier less than 1.0 that accounts for all factors causing illuminance to decrease over time, including lamp lumen depreciation, luminaire dirt depreciation, and room surface dirt depreciation.

Question 2

Equivalent Sphere Illumination (ESI) is a metric used to evaluate:

Accepted Answer

The quality of lighting in terms of visual task visibility

Answer

ESI converts actual lighting conditions to an equivalent sphere illumination value that accounts for veiling reflections and shadow effects, providing a measure of effective task visibility.

Question 3

An integrating sphere (Ulbricht sphere) is used to measure:

Accepted Answer

Total luminous flux output of a lamp or luminaire

Answer

An integrating sphere captures all light emitted by a source in all directions, enabling accurate measurement of total luminous flux in lumens regardless of light distribution.

Question 4

The Spacing Criterion (SC) for a luminaire indicates:

Accepted Answer

The maximum spacing-to-mounting-height ratio for acceptable illuminance uniformity

Answer

The Spacing Criterion defines the maximum ratio of luminaire spacing to mounting height above the work plane that still provides acceptable illuminance uniformity across the space.

Question 5

Mesopic vision occurs:

Accepted Answer

At intermediate luminance levels between photopic and scotopic ranges

Answer

Mesopic vision occurs at luminance levels between approximately 0.001 and 3 cd/m², where both rods and cones contribute jointly to visual perception.

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Photometry & Light Measurement 3