Arkansas AR-FO Fiber Optics
Contractor Practice Exam |
Questions, Verified Answers &
Detailed Rationales | Complete
Contractor License Exam Prep
Study Guide | Updated 2026
1. What is the primary function of a fiber-optic cable?
A. Conduct electrical current
B. Transmit information using light
C. Provide grounding for equipment
D. Increase electrical voltage
Answer: Transmit information using light
Rationale: Fiber-optic cable carries information as
optical signals rather than electrical signals, allowing
high bandwidth and excellent immunity to
electromagnetic interference.
2. Which fiber type is normally preferred for long-
distance telecommunications?
A. Plastic optical fiber
B. Multimode fiber
C. Single-mode fiber
D. Twin-lead fiber
Answer: Single-mode fiber
Rationale: Single-mode fiber has a small core and
supports very low modal dispersion, making it suitable
for long distances and high data rates.
,3. What is the typical core diameter of standard single-
mode fiber?
A. 9 mm
B. 50 mm
C. 62.5 mm
D. Approximately 9 µm
Answer: Approximately 9 µm
Rationale: Standard single-mode fiber has a core of
approximately 8–10 micrometers, commonly specified as
9/125 µm.
4. What is the typical core diameter of OM1 multimode
fiber?
A. 9 µm
B. 62.5 µm
C. 125 µm
D. 250 µm
Answer: 62.5 µm
Rationale: OM1 multimode fiber traditionally uses a
62.5-µm core with a 125-µm cladding diameter.
5. What does the 125 in a 9/125 fiber specification
represent?
A. Core diameter
B. Jacket thickness
C. Cladding diameter
D. Maximum wavelength
Answer: Cladding diameter
Rationale: A 9/125 fiber has an approximately 9-µm core
and 125-µm cladding diameter.
,6. Which phenomenon occurs when light strikes the
core-cladding boundary at an appropriate angle and
remains within the fiber?
A. Electrical induction
B. Total internal reflection
C. Radio-frequency coupling
D. Polarization loss
Answer: Total internal reflection
Rationale: Total internal reflection is the fundamental
optical principle that confines light within the fiber
core.
7. What is the main purpose of the fiber cladding?
A. Conduct electricity
B. Provide the outer jacket
C. Provide a lower refractive index around the core
D. Increase cable weight
Answer: Provide a lower refractive index around the
core
Rationale: The cladding surrounds the core and has a
lower refractive index, allowing the optical signal to
remain confined to the core.
8. What unit is commonly used to express optical
power?
A. Ohms
B. Watts per meter
C. dBm
D. Hertz
Answer: dBm
Rationale: Optical power levels are commonly measured
in dBm, which expresses power relative to 1 milliwatt.
, 9. What does dB measure in a fiber-optic system?
A. Absolute temperature
B. Cable diameter
C. A logarithmic ratio of power levels
D. Fiber core size
Answer: A logarithmic ratio of power levels
Rationale: Decibels express the ratio between two
power levels and are widely used for insertion loss and
gain calculations.
10. Which condition generally causes greater
attenuation in fiber?
A. Clean connectors
B. Proper bend radius
C. Excessive bending
D. Correctly installed splice sleeves
Answer: Excessive bending
Rationale: Excessive bending can cause macrobending
or microbending losses and may permanently damage
the fiber.
11. What is macrobending?
A. A microscopic defect in the glass
B. A relatively large-scale bend in the fiber
C. A connector contamination problem
D. A splice polishing defect
Answer: A relatively large-scale bend in the fiber
Rationale: Macrobending occurs when the fiber is bent
beyond its allowable radius, causing some optical power
to escape from the core.
Contractor Practice Exam |
Questions, Verified Answers &
Detailed Rationales | Complete
Contractor License Exam Prep
Study Guide | Updated 2026
1. What is the primary function of a fiber-optic cable?
A. Conduct electrical current
B. Transmit information using light
C. Provide grounding for equipment
D. Increase electrical voltage
Answer: Transmit information using light
Rationale: Fiber-optic cable carries information as
optical signals rather than electrical signals, allowing
high bandwidth and excellent immunity to
electromagnetic interference.
2. Which fiber type is normally preferred for long-
distance telecommunications?
A. Plastic optical fiber
B. Multimode fiber
C. Single-mode fiber
D. Twin-lead fiber
Answer: Single-mode fiber
Rationale: Single-mode fiber has a small core and
supports very low modal dispersion, making it suitable
for long distances and high data rates.
,3. What is the typical core diameter of standard single-
mode fiber?
A. 9 mm
B. 50 mm
C. 62.5 mm
D. Approximately 9 µm
Answer: Approximately 9 µm
Rationale: Standard single-mode fiber has a core of
approximately 8–10 micrometers, commonly specified as
9/125 µm.
4. What is the typical core diameter of OM1 multimode
fiber?
A. 9 µm
B. 62.5 µm
C. 125 µm
D. 250 µm
Answer: 62.5 µm
Rationale: OM1 multimode fiber traditionally uses a
62.5-µm core with a 125-µm cladding diameter.
5. What does the 125 in a 9/125 fiber specification
represent?
A. Core diameter
B. Jacket thickness
C. Cladding diameter
D. Maximum wavelength
Answer: Cladding diameter
Rationale: A 9/125 fiber has an approximately 9-µm core
and 125-µm cladding diameter.
,6. Which phenomenon occurs when light strikes the
core-cladding boundary at an appropriate angle and
remains within the fiber?
A. Electrical induction
B. Total internal reflection
C. Radio-frequency coupling
D. Polarization loss
Answer: Total internal reflection
Rationale: Total internal reflection is the fundamental
optical principle that confines light within the fiber
core.
7. What is the main purpose of the fiber cladding?
A. Conduct electricity
B. Provide the outer jacket
C. Provide a lower refractive index around the core
D. Increase cable weight
Answer: Provide a lower refractive index around the
core
Rationale: The cladding surrounds the core and has a
lower refractive index, allowing the optical signal to
remain confined to the core.
8. What unit is commonly used to express optical
power?
A. Ohms
B. Watts per meter
C. dBm
D. Hertz
Answer: dBm
Rationale: Optical power levels are commonly measured
in dBm, which expresses power relative to 1 milliwatt.
, 9. What does dB measure in a fiber-optic system?
A. Absolute temperature
B. Cable diameter
C. A logarithmic ratio of power levels
D. Fiber core size
Answer: A logarithmic ratio of power levels
Rationale: Decibels express the ratio between two
power levels and are widely used for insertion loss and
gain calculations.
10. Which condition generally causes greater
attenuation in fiber?
A. Clean connectors
B. Proper bend radius
C. Excessive bending
D. Correctly installed splice sleeves
Answer: Excessive bending
Rationale: Excessive bending can cause macrobending
or microbending losses and may permanently damage
the fiber.
11. What is macrobending?
A. A microscopic defect in the glass
B. A relatively large-scale bend in the fiber
C. A connector contamination problem
D. A splice polishing defect
Answer: A relatively large-scale bend in the fiber
Rationale: Macrobending occurs when the fiber is bent
beyond its allowable radius, causing some optical power
to escape from the core.
