CEM Lighting Systems and Controls 1 — Questions and Answers
Question 1: What is the efficacy of a standard T8 fluorescent lamp?
- 50-60 lumens/watt
- 75-95 lumens/watt (Correct answer)
- 100-120 lumens/watt
- 130-150 lumens/watt
Correct answer: 75-95 lumens/watt
Standard T8 fluorescent lamps produce approximately 75-95 lumens per watt, making them significantly more efficient than incandescent sources.
Question 2: Which lighting control strategy turns off lights when no occupancy is detected?
- Dimming control
- Occupancy sensor control (Correct answer)
- Daylight harvesting
- Lumen depreciation control
Correct answer: Occupancy sensor control
Occupancy sensor control automatically switches lights off when no motion or presence is detected, reducing energy waste in unoccupied spaces.
Question 3: Daylight harvesting saves energy by:
- Increasing lamp wattage during daytime
- Dimming electric lights in proportion to available natural light (Correct answer)
- Using mirrors to redirect sunlight
- Switching to a warmer color temperature during daylight hours
Correct answer: Dimming electric lights in proportion to available natural light
Daylight harvesting uses photosensors to dim or switch off electric lighting when sufficient natural daylight is available, reducing electricity consumption.
Question 4: What does the Color Rendering Index (CRI) measure?
- The color temperature of a lamp in Kelvin
- How accurately a light source renders colors compared to a reference source (Correct answer)
- The lumen output per watt of a lamp
- The beam angle of a directional luminaire
Correct answer: How accurately a light source renders colors compared to a reference source
CRI measures how faithfully a light source renders object colors compared to a natural reference source, with a perfect score of 100.
Question 5: LED lighting saves energy over fluorescent primarily because it:
- Operates at higher voltage
- Converts more electrical energy to light with less heat loss (Correct answer)
- Uses a longer warm-up cycle
- Requires ballasts that reduce power factor
Correct answer: Converts more electrical energy to light with less heat loss
LEDs convert a much higher percentage of electrical input into visible light, generating far less wasted heat than fluorescent or incandescent sources.
Question 6: A power factor correction capacitor added to a fluorescent lighting circuit will:
- Increase lamp lumens output
- Reduce reactive power demand and improve power factor (Correct answer)
- Increase lamp operating temperature
- Extend lamp life by reducing voltage
Correct answer: Reduce reactive power demand and improve power factor
Capacitors supply reactive power locally, reducing the reactive current drawn from the utility and improving the circuit power factor.
