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

One footcandle equals one lumen per square foot; since 1 square meter equals 10.76 square feet, 1 footcandle also equals 10.76 lux.

Question 2

Photopic vision refers to vision under:

Accepted Answer

Bright light conditions using cone cells

Answer

Photopic vision occurs under bright light conditions (above approximately 3 cd/m²) and is mediated primarily by cone cells, providing full color perception.

Question 3

Lamp efficacy is expressed in which units?

Accepted Answer

Lumens per watt

Answer

Efficacy measures how efficiently a lamp converts electrical power to visible light and is expressed as lumens per watt (lm/W).

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 CU is the ratio of lumens reaching the work plane to the total lumens produced by the lamps, accounting for room geometry and luminaire distribution characteristics.

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 RCR is calculated from the room length, width, and the vertical distance between the luminaire plane and work plane, describing the proportional geometry of the room cavity.

(CLD) Certified Lighting Designer Practice Test

(CLD) Certified Lighting Designer Practice Test

CLD Photometry & Light Measurement 2