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What is the definition of 'beam' in the context of lighting?

• B. A group of nearly parallel rays of light

• C. The effective length of a beam of light

• A. The angle of a light beam that intersects the candlepower distribution curve

• D. The cavity formed by the ceiling, a plane of suspended luminaires

What does the term 'spacing criteria' refer to in lighting design?

• D. A light loss factor that may be recovered by relamping

• C. A single number derived from the dimensions of a room cavity

• B. The ratio of the luminous flux reaching a specified work plane

• A. A formula for determining how far apart luminaires may be installed

What is the 'work plane' in lighting design?

• D. The cavity formed by the work plane, the floor, and the wall surfaces

• A. The horizontal plane at which work is done and on which illumination is specified

• B. A light loss factor representing the decrease in luminous output of a lamp

• C. A procedure for calculating the illumination produced on a surface by a point source

What is the 'lumen method' used for in lighting design?

• D. A procedure for determining the number and types of lamps required for uniform illumination

• C. A light loss factor representing the decrease in luminous output of a lamp

• B. A formula for determining how far apart luminaires may be installed

• A. A procedure for calculating the illumination produced on a surface by a point source

What is the 'room surface dirt depreciation' factor in lighting design?

• C. A light loss factor representing the decrease in reflected light resulting from dirt on room surfaces

• A. A light loss factor representing the decrease in luminous output of a luminaire

• D. A light loss factor that takes into account the effects of temperature and voltage drops

• B. A light loss factor that may be recovered by relamping