# Optical Fiber Cables

This set of Optical Communications Multiple Choice Questions & Answers (MCQs) focuses on ” Optical Fiber Cables”.

1. When optical fibers are to be installed in a working environment, the most important parameter to be considered is?
a) Transmission property of the fiber
b) Mechanical property of the fiber
c) Core cladding ratio of the fiber
d) Numerical aperture of the fiber

2. It is not important to cover these optical fibers required for transmission.
a) True
b) False

3. Optical fibers for communication use are mostly fabricated from ___________
a) Plastic
b) Silica or multicomponent glass
c) Ceramics
d) Copper

4. An Si-O bond with a Young’s modulus of 9*1010Nm-1 have an elliptical crack of depth 7nm. The surface energy is 2.29 J. Estimate fracture stress for silica fiber.
a) 4.32*109Nm-1
b) 6.32*109Nm-1
c) 5.2*109Nm-1
d) 3*109Nm-1

5. Calculate percentage strain at break for a Si-O bond with a fracture strength of 3.52*1010Nm-1 and Young’s modulus of 9 *109Nm-1.
a) 3.1 %
b) 2.8 %
c) 4.5 %
d) 3.9 %

6. Stress corrosion must be considered while designing and testing optical fiber cables.
a) True
b) False

7. Which statistics are used for calculations of strengths of optical fibers?
a) Edwin statistics
b) Newton statistics
c) Wei-bull statistics
d) Gamma statistics

8. What does n denotes in the equation given below, if vc is the crack velocity; A is the constant for the fiber material and KI is the strength intensity factor?

`vc = AKIn`

a) Refractive index
b) Stress corrosion susceptibility
c) Strain
d) Young’s modulus