CLC CLC Photometry & Color Science

Question 1

Which photometric quantity describes the total luminous flux emitted by a light source in all directions, measured in lumens?

Accepted Answer

Luminous flux

Answer

Luminous flux (measured in lumens) represents the total quantity of visible light emitted by a source in all directions.

Question 2

The Color Rendering Index (CRI) measures a light source's ability to reveal colors compared to which reference source?

Accepted Answer

A natural or reference illuminant

Answer

CRI compares how accurately a light source renders object colors relative to a reference illuminant (daylight or incandescent, depending on CCT).

Question 3

A luminaire with an IES Type II photometric distribution is most appropriate for which application?

Accepted Answer

Roadway / streetlighting on a two-lane road

Answer

IES Type II distribution provides a medium-spread pattern suited for roadway and streetlighting on two-lane roads.

Question 4

Correlated Color Temperature (CCT) is measured in which unit?

Accepted Answer

Kelvin

Answer

CCT is expressed in Kelvin (K) and describes the color appearance of a light source from warm (2700K) to cool (6500K+).

Question 5

Luminance is defined as luminous intensity per unit of what?

Accepted Answer

Projected area of the source

Answer

Luminance (cd/m²) equals luminous intensity divided by the projected area of the emitting surface, describing perceived brightness.

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