EGEE 102 Exam 3 ACTUAL Exam
Questions and CORRECT Answers
Lesson 6 - CORRECT ANSWER
What is the most common measure of light output (or luminous flux)? - CORRECT
ANSWER Lumen
The high-pressure sodium (HPS) lamp is widely used for what purpose? - CORRECT
ANSWER Outdoor and industrial applications
Which one of the following light bulbs produces highest lumens per watt? - CORRECT
ANSWER Low pressure sodium
What are the units of measuring light? - CORRECT ANSWER Lumens
What is the minimum amount of illumination that is required for reading? - CORRECT
ANSWER 50 fc
The luminous efficacy of a tungsten lamp is about 12 lumens/watt. What is the efficacy of a
fluorescent tube (in lumens/watt)? - CORRECT ANSWER 50
General purpose lighting in hallways is also called _____ lighting. - CORRECT
ANSWER ambient
A 120 watt incandescent light bulb is operated for 6 hours, and a 15 watt fluorescent light bulb is
operated for the same period of time. At 8 cents per kWh, what is the cost savings of the
fluorescent bulb? - CORRECT ANSWER $ 0.05
, A 60-watt light bulb produces 4.5 watts of radiant energy and 55.5 watts of heat energy. What is
its efficiency? - CORRECT ANSWER Efficiency = 4.5/60 = 0.075 = 7.5 %
A 120-watt light bulb is left on for 38 hours. How much did it cost to operate the light bulb if
electricity costs 5 cents per kWh? - CORRECT ANSWER $ 0.23
Energy consumed = x 38 = 4.56 kWh
Energy cost = 4.56 x = $0.228 = $0.23
To save energy and money, Jackie Smith replaced the 100 Watt incandescent light bulb in her
house with a 23 Watt CFL bulb. The expected life of incandescent and CFL bulbs is 1000 and
8000 hours respectively. The purchase price of an incandescent bulb is $0.56 and for the CFL it
is $5.98. The cost of electricity is 7 cents per kWh. What is her total savings over the life time of
the CFL? - CORRECT ANSWER $ 41.62
A 15 watt compact fluorescent lamp produces 1503 lumens of light. What is the efficacy of the
CFL (in lumens/watt)? - CORRECT ANSWER 100.2 lumens/watt
Efficacy = 1503/15 = 100.2 lumens/watt
By approximately what percentage can lighting energy costs be reduced with the use of modern
technology? - CORRECT ANSWER 50 percent
What lighting method is most energy efficient? - CORRECT ANSWER High intensity
discharge
A footcandle (fc) is calculated as _____. - CORRECT ANSWER fc = Lumens of Light / Area
in sq. ft
A 100 watt incandescent light bulb is operated for 12 hours, and a 15 watt fluorescent light bulb
is operated for the same period of time. At 10 cents per kWh, what is the cost savings in using
the fluorescent bulb? - CORRECT ANSWER 0.102
Questions and CORRECT Answers
Lesson 6 - CORRECT ANSWER
What is the most common measure of light output (or luminous flux)? - CORRECT
ANSWER Lumen
The high-pressure sodium (HPS) lamp is widely used for what purpose? - CORRECT
ANSWER Outdoor and industrial applications
Which one of the following light bulbs produces highest lumens per watt? - CORRECT
ANSWER Low pressure sodium
What are the units of measuring light? - CORRECT ANSWER Lumens
What is the minimum amount of illumination that is required for reading? - CORRECT
ANSWER 50 fc
The luminous efficacy of a tungsten lamp is about 12 lumens/watt. What is the efficacy of a
fluorescent tube (in lumens/watt)? - CORRECT ANSWER 50
General purpose lighting in hallways is also called _____ lighting. - CORRECT
ANSWER ambient
A 120 watt incandescent light bulb is operated for 6 hours, and a 15 watt fluorescent light bulb is
operated for the same period of time. At 8 cents per kWh, what is the cost savings of the
fluorescent bulb? - CORRECT ANSWER $ 0.05
, A 60-watt light bulb produces 4.5 watts of radiant energy and 55.5 watts of heat energy. What is
its efficiency? - CORRECT ANSWER Efficiency = 4.5/60 = 0.075 = 7.5 %
A 120-watt light bulb is left on for 38 hours. How much did it cost to operate the light bulb if
electricity costs 5 cents per kWh? - CORRECT ANSWER $ 0.23
Energy consumed = x 38 = 4.56 kWh
Energy cost = 4.56 x = $0.228 = $0.23
To save energy and money, Jackie Smith replaced the 100 Watt incandescent light bulb in her
house with a 23 Watt CFL bulb. The expected life of incandescent and CFL bulbs is 1000 and
8000 hours respectively. The purchase price of an incandescent bulb is $0.56 and for the CFL it
is $5.98. The cost of electricity is 7 cents per kWh. What is her total savings over the life time of
the CFL? - CORRECT ANSWER $ 41.62
A 15 watt compact fluorescent lamp produces 1503 lumens of light. What is the efficacy of the
CFL (in lumens/watt)? - CORRECT ANSWER 100.2 lumens/watt
Efficacy = 1503/15 = 100.2 lumens/watt
By approximately what percentage can lighting energy costs be reduced with the use of modern
technology? - CORRECT ANSWER 50 percent
What lighting method is most energy efficient? - CORRECT ANSWER High intensity
discharge
A footcandle (fc) is calculated as _____. - CORRECT ANSWER fc = Lumens of Light / Area
in sq. ft
A 100 watt incandescent light bulb is operated for 12 hours, and a 15 watt fluorescent light bulb
is operated for the same period of time. At 10 cents per kWh, what is the cost savings in using
the fluorescent bulb? - CORRECT ANSWER 0.102
