CEM Lighting Systems and Controls 2

Question 1

What is lumen depreciation?

Accepted Answer

The gradual decrease in light output as a lamp ages

Answer

Lumen depreciation refers to the reduction in light output that occurs over a lamp's service life due to phosphor degradation and other aging factors.

Question 2

Which ballast type provides the greatest energy savings for fluorescent lamps?

Accepted Answer

Electronic high-frequency ballast

Answer

Electronic high-frequency ballasts operate lamps at 20,000+ Hz, eliminating flicker losses and running more efficiently than magnetic ballasts.

Question 3

The Lighting Power Density (LPD) metric is expressed in:

Accepted Answer

Watts per square foot

Answer

LPD is expressed as watts per square foot (or W/m²) and is used in energy codes to limit installed lighting power in buildings.

Question 4

Task-ambient lighting design saves energy compared to uniform lighting by:

Accepted Answer

Providing higher illuminance only at work surfaces and lower levels elsewhere

Answer

Task-ambient systems deliver high light levels where needed for visual tasks while maintaining lower ambient levels, reducing total installed wattage.

Question 5

In a lighting retrofit, the simple payback period is calculated as:

Accepted Answer

Installed cost divided by annual savings

Answer

Simple payback is the initial investment divided by annual energy and maintenance savings, expressing how many years it takes to recover the cost.

CEM - Certified Energy Manager Practice Test

CEM - Certified Energy Manager Practice Test

CEM Lighting Systems and Controls 2