CO Fiber Optics Contractor Exam
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
Download Pdf.
1. Which fiber-optic cable type is generally preferred for long-distance
backbone links because it has lower attenuation and supports
higher bandwidth over greater distances?
A. Category 5e copper cable
B. Coaxial cable
C. Single-mode fiber
D. Twinaxial cable
Single-mode fiber has a very small core that permits essentially one
propagation mode, resulting in low attenuation and high bandwidth
over long distances.
2. What is the primary function of the cladding surrounding the core
of an optical fiber?
A. Increase electrical conductivity
B. Confine light within the core through total internal reflection
C. Provide power to active equipment
D. Prevent all mechanical bending
,The cladding has a lower refractive index than the core, allowing light to
remain confined within the core through total internal reflection.
3. Which fiber type is most commonly identified by an approximately
50 µm or 62.5 µm core?
A. Single-mode fiber
B. Multimode fiber
C. Plastic-coated copper
D. Coaxial fiber
Multimode fiber uses a larger core, commonly 50 µm or 62.5 µm,
allowing multiple light modes to propagate simultaneously.
4. What is the main purpose of an optical time-domain reflectometer
(OTDR)?
A. Supply electrical power to fiber equipment
B. Convert Ethernet signals into radio signals
C. Locate events, losses, reflections, and faults along an optical fiber
D. Clean fiber connectors automatically
An OTDR sends optical pulses into the fiber and analyzes returned light
to identify events such as splices, connectors, bends, breaks, and
attenuation along the cable.
5. Before mating two fiber-optic connectors, what is the most
important preparation step?
A. Apply electrical contact grease
B. Increase transmitter power
,C. Inspect and clean the connector end faces
D. Twist the connectors together repeatedly
Contamination on fiber end faces can cause insertion loss, back
reflection, and permanent damage, so inspection and cleaning are
essential before connection.
6. Which measurement describes the amount of optical power lost as
a signal travels through a fiber link?
A. Return frequency
B. Voltage drop
C. Insertion loss
D. Modulation index
Insertion loss represents the reduction in optical power caused by
components and connections in the optical path and is normally
expressed in decibels.
7. Which unit is commonly used to express optical power levels in
fiber-optic systems?
A. Ohms
B. Amperes
C. dBm
D. Hertz
dBm expresses optical power relative to 1 milliwatt and is widely used
for measuring transmitter output and receiver power levels.
, 8. A fiber link has an input power of 0 dBm and an output power of −3
dBm. Approximately how much loss does the link have?
A. 0 dB
B. 1 dB
C. 3 dB
D. 30 dB
The difference between 0 dBm and −3 dBm is 3 dB, so the measured
optical loss is approximately 3 dB.
9. Which condition is most likely to cause excessive insertion loss at a
fiber connector?
A. Correctly polished and clean end faces
B. Properly aligned ferrules
C. Dirt or contamination on the end face
D. Correct connector mating
Dirt, dust, oil, or other contamination can interfere with optical
alignment and transmission, producing excessive insertion loss.
10. What is the purpose of a fusion splicer?
A. Measure cable jacket thickness
B. Convert light into radio frequency energy
C. Permanently join two optical fibers by fusing their glass together
D. Generate electrical power for the fiber
A fusion splicer precisely aligns fiber cores and uses an electric arc to
fuse the glass ends into a low-loss permanent splice.
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
Download Pdf.
1. Which fiber-optic cable type is generally preferred for long-distance
backbone links because it has lower attenuation and supports
higher bandwidth over greater distances?
A. Category 5e copper cable
B. Coaxial cable
C. Single-mode fiber
D. Twinaxial cable
Single-mode fiber has a very small core that permits essentially one
propagation mode, resulting in low attenuation and high bandwidth
over long distances.
2. What is the primary function of the cladding surrounding the core
of an optical fiber?
A. Increase electrical conductivity
B. Confine light within the core through total internal reflection
C. Provide power to active equipment
D. Prevent all mechanical bending
,The cladding has a lower refractive index than the core, allowing light to
remain confined within the core through total internal reflection.
3. Which fiber type is most commonly identified by an approximately
50 µm or 62.5 µm core?
A. Single-mode fiber
B. Multimode fiber
C. Plastic-coated copper
D. Coaxial fiber
Multimode fiber uses a larger core, commonly 50 µm or 62.5 µm,
allowing multiple light modes to propagate simultaneously.
4. What is the main purpose of an optical time-domain reflectometer
(OTDR)?
A. Supply electrical power to fiber equipment
B. Convert Ethernet signals into radio signals
C. Locate events, losses, reflections, and faults along an optical fiber
D. Clean fiber connectors automatically
An OTDR sends optical pulses into the fiber and analyzes returned light
to identify events such as splices, connectors, bends, breaks, and
attenuation along the cable.
5. Before mating two fiber-optic connectors, what is the most
important preparation step?
A. Apply electrical contact grease
B. Increase transmitter power
,C. Inspect and clean the connector end faces
D. Twist the connectors together repeatedly
Contamination on fiber end faces can cause insertion loss, back
reflection, and permanent damage, so inspection and cleaning are
essential before connection.
6. Which measurement describes the amount of optical power lost as
a signal travels through a fiber link?
A. Return frequency
B. Voltage drop
C. Insertion loss
D. Modulation index
Insertion loss represents the reduction in optical power caused by
components and connections in the optical path and is normally
expressed in decibels.
7. Which unit is commonly used to express optical power levels in
fiber-optic systems?
A. Ohms
B. Amperes
C. dBm
D. Hertz
dBm expresses optical power relative to 1 milliwatt and is widely used
for measuring transmitter output and receiver power levels.
, 8. A fiber link has an input power of 0 dBm and an output power of −3
dBm. Approximately how much loss does the link have?
A. 0 dB
B. 1 dB
C. 3 dB
D. 30 dB
The difference between 0 dBm and −3 dBm is 3 dB, so the measured
optical loss is approximately 3 dB.
9. Which condition is most likely to cause excessive insertion loss at a
fiber connector?
A. Correctly polished and clean end faces
B. Properly aligned ferrules
C. Dirt or contamination on the end face
D. Correct connector mating
Dirt, dust, oil, or other contamination can interfere with optical
alignment and transmission, producing excessive insertion loss.
10. What is the purpose of a fusion splicer?
A. Measure cable jacket thickness
B. Convert light into radio frequency energy
C. Permanently join two optical fibers by fusing their glass together
D. Generate electrical power for the fiber
A fusion splicer precisely aligns fiber cores and uses an electric arc to
fuse the glass ends into a low-loss permanent splice.
