CO Fiber Optic Installer Contractor
Exam Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary function of an optical fiber’s core?
A. Provide mechanical protection
B. Block outside light
C. Transmit light signals
D. Reflect cladding light
Rationale: The core carries the actual light signal and is the main
transmission medium.
2. Which material is most commonly used for modern fiber optic cores?
A. Plastic
B. Glass (silica)
C. Copper
D. Aluminum
Rationale: Most telecommunications-grade fibers use silica glass due to
low attenuation.
,3. The numerical aperture (NA) of a fiber primarily affects:
A. Fiber tensile strength
B. Light acceptance angle
C. Jacket flexibility
D. Connector type
Rationale: NA determines the amount of light the fiber can accept and
guide.
4. Single-mode fiber typically has a core diameter of:
A. 100 microns
B. 62.5 microns
C. 50 microns
D. 8–10 microns
Rationale: SM fiber uses a very small core to allow only one propagation
mode.
5. Which type of fiber is best for long-distance, high-bandwidth
transmission?
A. Plastic optical fiber
B. Multimode step index
C. Multimode graded index
D. Single-mode fiber
Rationale: SM fiber supports long-distance transmission due to low
dispersion.
6. The protective coating surrounding the cladding is called:
, A. Jacket
B. Primary buffer coating
C. Strength member
D. Sheath
Rationale: The primary buffer protects the glass from microbending and
moisture.
7. Which wavelength is commonly used for long-haul fiber transmission?
A. 550 nm
B. 800 nm
C. 980 nm
D. 1550 nm
Rationale: 1550 nm has the lowest attenuation window in silica fibers.
8. Attenuation is measured in:
A. Lumens
B. Candela
C. dB/km
D. Watts
Rationale: Fiber loss is expressed as decibels per kilometer.
9. Dispersion in fiber optics refers to:
A. Mechanical bending
B. Fiber strength deterioration
C. Pulse spreading over distance
D. Excessive splice heat
Exam Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary function of an optical fiber’s core?
A. Provide mechanical protection
B. Block outside light
C. Transmit light signals
D. Reflect cladding light
Rationale: The core carries the actual light signal and is the main
transmission medium.
2. Which material is most commonly used for modern fiber optic cores?
A. Plastic
B. Glass (silica)
C. Copper
D. Aluminum
Rationale: Most telecommunications-grade fibers use silica glass due to
low attenuation.
,3. The numerical aperture (NA) of a fiber primarily affects:
A. Fiber tensile strength
B. Light acceptance angle
C. Jacket flexibility
D. Connector type
Rationale: NA determines the amount of light the fiber can accept and
guide.
4. Single-mode fiber typically has a core diameter of:
A. 100 microns
B. 62.5 microns
C. 50 microns
D. 8–10 microns
Rationale: SM fiber uses a very small core to allow only one propagation
mode.
5. Which type of fiber is best for long-distance, high-bandwidth
transmission?
A. Plastic optical fiber
B. Multimode step index
C. Multimode graded index
D. Single-mode fiber
Rationale: SM fiber supports long-distance transmission due to low
dispersion.
6. The protective coating surrounding the cladding is called:
, A. Jacket
B. Primary buffer coating
C. Strength member
D. Sheath
Rationale: The primary buffer protects the glass from microbending and
moisture.
7. Which wavelength is commonly used for long-haul fiber transmission?
A. 550 nm
B. 800 nm
C. 980 nm
D. 1550 nm
Rationale: 1550 nm has the lowest attenuation window in silica fibers.
8. Attenuation is measured in:
A. Lumens
B. Candela
C. dB/km
D. Watts
Rationale: Fiber loss is expressed as decibels per kilometer.
9. Dispersion in fiber optics refers to:
A. Mechanical bending
B. Fiber strength deterioration
C. Pulse spreading over distance
D. Excessive splice heat
