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

Efficiency of electrical distribution to the luminaire

Answer

Ratio of horizontal to vertical illuminance

Answer

Color shift of lamps at end of rated life

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

The total spherical lumen output of a luminaire

Answer

The uniformity ratio of illuminance across a room

Answer

The color rendering ability of a light source

Question 3

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

Accepted Answer

Total luminous flux output of a lamp or luminaire

Answer

Directional luminous intensity distribution at specific angles

Answer

Spectral power distribution at a single measurement angle

Answer

Illuminance at a defined work plane distance

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 minimum distance from a wall to the nearest luminaire row

Answer

The maximum number of luminaires permitted per branch circuit

Answer

The maximum allowable wattage per square foot of floor area

Question 5

Mesopic vision occurs:

Accepted Answer

At intermediate luminance levels between photopic and scotopic ranges

Answer

Only under full daylight conditions above 100 lux

Answer

Only under complete darkness below 0.001 cd/m²

Answer

When viewing monochromatic light sources exclusively

Question 6

Luminous exitance (M) describes:

Accepted Answer

Total luminous flux leaving a surface per unit area

Answer

Luminous flux incident on a surface per unit area

Answer

Luminous intensity emitted by a point source in a given direction

Answer

Luminance of a surface as perceived from a viewing angle

Question 7

The Unified Glare Rating (UGR) is used to assess:

Accepted Answer

Discomfort glare from luminaires in interior lighting installations

Answer

Total glare impact from floodlights in outdoor sports facilities

Answer

Minimum emergency egress illuminance levels

Answer

Contrast ratio and visual comfort of electronic display screens