CEM Lighting Systems 2

Question 1

A warehouse currently uses 400W metal halide fixtures. Replacing them with 150W LED high-bays maintains light levels. What is the percentage energy reduction?

Accepted Answer

62.5%

Answer

Energy reduction = (400-150)/400 × 100 = 62.5%.

Question 2

Which lighting control strategy automatically reduces output based on available daylight near perimeter windows?

Accepted Answer

Daylight harvesting

Answer

Daylight harvesting uses photosensors to dim electric lights as natural light increases.

Question 3

The Color Rendering Index (CRI) measures which lamp characteristic?

Accepted Answer

Accuracy of color appearance compared to a reference source

Answer

CRI rates how accurately a light source renders object colors relative to a reference illuminant on a 0–100 scale.

Question 4

An office space requires 50 foot-candles at the work plane. The room has an area of 2,000 sq ft and luminaires with 3,200 lumens each. Using a CU of 0.65 and LLF of 0.80, how many luminaires are needed?

Accepted Answer

60

Answer

N = (50 × 2000) / (3200 × 0.65 × 0.80) = 100,000 / 1,664 ≈ 60 luminaires.

Question 5

Which term describes the fraction of lamp lumens that actually reach the work plane, accounting for fixture efficiency and room geometry?

Accepted Answer

Coefficient of Utilization (CU)

Answer

The Coefficient of Utilization (CU) represents the ratio of lumens reaching the work plane to total lamp lumens.

(CEM) Certified Emergency Manager Practice Test

(CEM) Certified Emergency Manager Practice Test

CEM Lighting Systems 2