CLD Photometry & Light Measurement 2

Question 1

One footcandle is equal to:

Accepted Answer

Both 1 lumen per square foot and 10.76 lux

Answer

1 lumen per square foot only

Answer

10.76 lux only

Answer

1 candela per square foot

Question 2

Photopic vision refers to vision under:

Accepted Answer

Bright light conditions using cone cells

Answer

Low light conditions using rod cells

Answer

Intermediate light conditions using both rods and cones

Answer

Ultraviolet light conditions

Question 3

Lamp efficacy is expressed in which units?

Accepted Answer

Lumens per watt

Answer

Watts per lumen

Answer

Candela per watt

Answer

Lux per watt

Question 4

The Coefficient of Utilization (CU) in a lighting calculation represents:

Accepted Answer

The ratio of lumens reaching the work plane to total lamp lumens

Answer

The light loss due to dirt accumulation on luminaires

Answer

The lumen output per watt of input power

Answer

The ratio of direct to indirect illumination

Question 5

In the zonal cavity method, the Room Cavity Ratio (RCR) is determined by:

Accepted Answer

Room dimensions including length, width, and cavity height

Answer

The reflectance of luminaire surfaces only

Answer

Maintenance factors and lamp lumen depreciation

Answer

The lamp lumen output and wattage

Question 6

Maintained illuminance refers to:

Accepted Answer

The average illuminance level at which maintenance should be performed

Answer

The maximum illuminance at the time of lamp installation

Answer

The illuminance measured at the ceiling plane

Answer

The illuminance provided by emergency backup lighting

Question 7

Veiling reflections reduce visual task performance by:

Accepted Answer

Superimposing specular reflections from bright sources onto the task surface, reducing contrast

Answer

Increasing the contrast of visual task details

Answer

Reducing the correlated color temperature of reflected light

Answer

Increasing illuminance levels at the task plane