provide an illuminance of 500 lx for an office 6×15mif the coefficient of utilization is calculated at 0.55, the maintenance factor can be ignored and the luminaire efficacy is 60 lm/W is (a) 90 (b) 21 (c) 10 (d) 15

1.The single factor in the following list which does not affect the coefficient

 

of utilisation is

(a) the mounting height of the luminaires

(b) the room size

(c) the colours and textures of the wall and ceiling finishes

(d) the required illuminances

2. The number of 65Wfluorescent luminaires which will be required to provide an illuminance of 500 lx for an office 6×15mif the coefficient of utilization is calculated at 0.55, the maintenance factor can be ignored and the luminaire efficacy is 60 lm/W is

(a) 90 (b) 21 (c) 10 (d) 15

3.The usual gas filling for a GLS filament lamp is

(a) argon and nitrogen (b) oxygen

(c) helium (d) air

4. A lamp reflector with the ability to reflect visible light but to transmit heat is referred to as

(a) overheated (b) silvered

(c) dichroic (d) tungsten–halogen

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