ETA Fiber Optic Installer Certification -
Study Guide Questions With Accurate
Solutions 2025
Light is electromagnetic energy with a _____ frequency and a _____ wavelength
compared to radios. CORRECT ANSWERS Higher; shorter
What type of light is used in fiber optic transmissions? CORRECT ANSWERS Infrared
(IR)
What are the four items needed for a fiber optic system to work? CORRECT ANSWERS
Transmitter, fiber optic cable, receiver, and connector
1 mW is the same as what in dBm? CORRECT ANSWERS 0 dBm (absolute power)
How is the power measured in fiber optics? CORRECT ANSWERS dBm
What fiber optic wavelength has the lowest loss? CORRECT ANSWERS 1550 nm
wavelength
What wavelength windows are used most for fiber optic communications? CORRECT
ANSWERS 850 nm, 1300 nm, and 1550 nm wavelengths
What year was fiber optic cable first used in commercial telephone systems in the U.S.?
CORRECT ANSWERS 1977
What light source is used for singlemode fiber? CORRECT ANSWERS Laser diode
What two light sources are used with multimode fiber? CORRECT ANSWERS LED and
VCSEL
All wavelengths of light travel at the same speed. (true or false; why) CORRECT
ANSWERS False; different wavelengths of light travel at different velocities
Which type of fiber has the larger core size: singlemode or multimode? CORRECT
ANSWERS Multimode
What is OSHA responsible for? CORRECT ANSWERS OSHA is responsible for
enforcing it's standards on regulated entities
What are two ways to reduce modal dispersion? CORRECT ANSWERS Use a smaller
core; use graded-index fiber
, What happens to the wavelength in fiber when the number of modes increase?
CORRECT ANSWERS The wavelength gets shorter with more modes
Where does Fresnel reflection occur? CORRECT ANSWERS Air gas and mechanical
interconnections
What is it called when light bends when moving between water and air? CORRECT
ANSWERS Refraction
What is the refractive index of the core and cladding of fiber? CORRECT ANSWERS
Core - 1.457 and 1.451; cladding - 1.42
Singlemode fiber systems usually operate at what three wavelengths? CORRECT
ANSWERS 1310 nm, 1550 nm, and 1625 nm wavelengths
What two multimode wavelengths are the most commonly used? CORRECT
ANSWERS 850 nm and 1300 nm wavelengths
How is attenuation measured? CORRECT ANSWERS Decibels (dB)
What is a "mode" in fiber? CORRECT ANSWERS A path of light
What will happen to the tensile strength of a fiber cable if it is bent more than
recommended? CORRECT ANSWERS The tensile strength decreases
OM3 and OM4 multimode fibers are known as what type of fiber? CORRECT
ANSWERS Laser optimized multimode fiber
What are the two most common core and cladding sizes in multimode fiber? CORRECT
ANSWERS 62.5/125 um (US); 50/125 um (EU)
What is the buffer size for a fiber used in tight buffered cables? CORRECT ANSWERS
900 um
What jacket color does singlemode fiber have? CORRECT ANSWERS Yellow
What are the 12 fiber color codes in order? CORRECT ANSWERS Blue, Orange,
Green, Brown, Slate, White, Red, Black, Yellow, Violet, Rose, Aqua
OM1 and OM2 are known as what types of fibers? CORRECT ANSWERS Legacy
multimode fibers
Why does graded-index fiber use numerous concentric layers of glass? CORRECT
ANSWERS Reduce modal dispersion
Study Guide Questions With Accurate
Solutions 2025
Light is electromagnetic energy with a _____ frequency and a _____ wavelength
compared to radios. CORRECT ANSWERS Higher; shorter
What type of light is used in fiber optic transmissions? CORRECT ANSWERS Infrared
(IR)
What are the four items needed for a fiber optic system to work? CORRECT ANSWERS
Transmitter, fiber optic cable, receiver, and connector
1 mW is the same as what in dBm? CORRECT ANSWERS 0 dBm (absolute power)
How is the power measured in fiber optics? CORRECT ANSWERS dBm
What fiber optic wavelength has the lowest loss? CORRECT ANSWERS 1550 nm
wavelength
What wavelength windows are used most for fiber optic communications? CORRECT
ANSWERS 850 nm, 1300 nm, and 1550 nm wavelengths
What year was fiber optic cable first used in commercial telephone systems in the U.S.?
CORRECT ANSWERS 1977
What light source is used for singlemode fiber? CORRECT ANSWERS Laser diode
What two light sources are used with multimode fiber? CORRECT ANSWERS LED and
VCSEL
All wavelengths of light travel at the same speed. (true or false; why) CORRECT
ANSWERS False; different wavelengths of light travel at different velocities
Which type of fiber has the larger core size: singlemode or multimode? CORRECT
ANSWERS Multimode
What is OSHA responsible for? CORRECT ANSWERS OSHA is responsible for
enforcing it's standards on regulated entities
What are two ways to reduce modal dispersion? CORRECT ANSWERS Use a smaller
core; use graded-index fiber
, What happens to the wavelength in fiber when the number of modes increase?
CORRECT ANSWERS The wavelength gets shorter with more modes
Where does Fresnel reflection occur? CORRECT ANSWERS Air gas and mechanical
interconnections
What is it called when light bends when moving between water and air? CORRECT
ANSWERS Refraction
What is the refractive index of the core and cladding of fiber? CORRECT ANSWERS
Core - 1.457 and 1.451; cladding - 1.42
Singlemode fiber systems usually operate at what three wavelengths? CORRECT
ANSWERS 1310 nm, 1550 nm, and 1625 nm wavelengths
What two multimode wavelengths are the most commonly used? CORRECT
ANSWERS 850 nm and 1300 nm wavelengths
How is attenuation measured? CORRECT ANSWERS Decibels (dB)
What is a "mode" in fiber? CORRECT ANSWERS A path of light
What will happen to the tensile strength of a fiber cable if it is bent more than
recommended? CORRECT ANSWERS The tensile strength decreases
OM3 and OM4 multimode fibers are known as what type of fiber? CORRECT
ANSWERS Laser optimized multimode fiber
What are the two most common core and cladding sizes in multimode fiber? CORRECT
ANSWERS 62.5/125 um (US); 50/125 um (EU)
What is the buffer size for a fiber used in tight buffered cables? CORRECT ANSWERS
900 um
What jacket color does singlemode fiber have? CORRECT ANSWERS Yellow
What are the 12 fiber color codes in order? CORRECT ANSWERS Blue, Orange,
Green, Brown, Slate, White, Red, Black, Yellow, Violet, Rose, Aqua
OM1 and OM2 are known as what types of fibers? CORRECT ANSWERS Legacy
multimode fibers
Why does graded-index fiber use numerous concentric layers of glass? CORRECT
ANSWERS Reduce modal dispersion
