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.
CEM Lighting Systems and Controls 1
What is the efficacy of a standard T8 fluorescent lamp?