Start Practice Exam Test Questions
Direction: Either Supply the missing word(s) in each statement or Choose the letter that best answers each question.
1. Fiber-optic cables carry _____ rather than electrical signals.
2. The three main types of information carried by fiber optic-cables are _____, _____, and _____.
3. The major use of fiber-optic cables is in _____.
4. Fiber-optic cables are made of _____ or _____.
5. The main benefit of fiber-optic cable over electric cable is its _____.
6. True or false. Fiber-optic cable has more loss than electric cable over long distances.
7. True or false. Fiber-optic cable is smaller, lighter, and stronger than electric cable.
8. List the two main disadvantages of fiber optic cable.
9. The two most commonly used light sources in fiber-optic systems are _____.
10. Voice and video signals are converted into before being transmitted by a light beam.
11. The device that converts the light pulses into an electrical signal is a(n) _____.
12. Regenerative units called _____ are often used to compensate for signal attenuation over long distances.
13. Light is a type of _____ radiation.
14. A fiber-optic cable can be viewed as a light _____.
15. Light travels in a
- a. Circle
- b. Straight line
- c. Curve
- d. Random way
16. The wavelength of light is usually expressed in _____ or _____.
17. The lowest-frequency visible light is
- a. Red
- b. Violet
18. A micrometer, or micron, is a length of _____ of a _____.
19. The wavelength range of visible light is _____ to _____ nm.
20. Infrared light has a wavelength that is
- a. Less than 400 nm
- b. More than 700 nm
- c. Less than 700 nm
21. The optical spectrum is made up of what three parts?
22. The speed of light in air is _____ m/s or _____ mi/s.
23. True or false. The speed of light is slower in glass or water than it is in air.
24. The number that tells how fast light travels in a medium compared to air is the _____ of _____.
25. Light beams can be bounced or their direction can be changed by _____ with a(n) _____.
26. The bending of light rays due to speed changes when moving from one medium to another is called _____.
27. If a light ray strikes a mirror at an angle of 30° from the normal, it is reflected at an angle of _____ ° from the normal.
28. When the angle of refraction is 90° to the normal, the ray travels along the _____ between the two media. Therefore, the incident ray strikes the surface at the _____ angle.
29. When the incident ray strikes the interface at an angle greater than the critical angle, _____ occurs.
30. The critical angle depends upon the value of the _____ of _____.
31. Which material has the best optical characteristics and lowest loss?
- a. Plastic
- b. Glass
- c. they are equal
32. The core is protected by the _____.
33. In PCS cable, the core is _____ and the cladding is _____.
34. The index of refraction is highest in the
- a. Core
- b. Cladding
35. List the three main types of fiber-optic cable.
36. Stretching of the light pulse is called _____.
37. List the two types of cable in which light pulse stretching occurs.
38. High-frequency pulses can be best transmitted over _____ cable.
39. Pulse stretching causes the information capacity of a cable to
- a. Increase
- b. Decrease
40. Graded index means that the _____ of _____ of the core varies over its cross section
41. Single-mode step-index cable has a Core diameter in the range of
- a. 100 to 1000 m
- b. 50 to 100 m
- c. 2 to 15 m
42. A _____ is applied over the cladding to protect against moisture, damage, etc.
43. A common protective layer in a cable is made of _____ mesh.
44. Fiber-optic cables are available with the following number of cores: _____.
45. Light loss in a cable is called _____.
46. Light loss is caused by _____.
47. Light loss is measured in _____ per_____.
48. A cable with a loss of 5 dB will have _____ percent of the input appear at the output (see Fig. 13-19). (page 365-Frenzel)
49. True or false. A kilometer is longer than a mile.
50. Which cable length will have the least attenuation?
- a. 40 ft
- b. 120 ft
- c. 1780 ft
- d. 1 km
51. Three cables with attenuations of 9, 22, and 45 dB are spliced together. The total attenuation is _____ dB.
52. True or false. Fiber-optic cables may be spliced.
53. To conveniently link and attach fiber-optic cables to one another and related equipment, _____ are used.
54. The two most common light sources used in fiber-optic transmitters are _____.
55.The most popular light wavelength is _____ m because fiber-optic cable attenuation is lowest at that wavelength.
56.True or false. The light from a 1.55 m LED is visible.
57. Usually LEDs are made of _____.
58. Single frequency light is called _____.
59. The condition of all emitted light waves being in phase is known as _____.
60. A single-frequency intense light source is known as a(n) _____.
61. The reflective surfaces on a laser diode structure form a(n) _____ that produces in-phase light waves.
62. For normal operation, LED and ILDs are _____ (reverse, forward)-biased.
63. Which is faster, an LED or ILD?
64. Which produces the brightest light, an LED or ILD?
65. During normal operation, all photodiodes are _____ (reverse, forward)-biased.
66. Light falling on the PN junction of a photodiode causes the diode's _____ current to increase.
67. The most sensitive and fastest light detector is the _____.
68. 68-.The two main circuits in a fiber-optic receiver are _____.
69. The product of the bit rate and distance of a system is 90 Mbits·km/s. The rating at 3 km is _____ Mbits/s.
70. In today's systems, the average maximum distance between repeaters is between _____ and _____ mi.