Which Sadhana is Best by Sumit Girdharwal Ji & Sri Yogeshwaranand Ji. विश्व के पटल पर अनेकों साधक ऐसे हैं, जो निरन्तर साधना में रत् रहते हैं, परन्तु उन्हें अभीष्ट की प्राप्ति नहीं होती। इसी प्रक...
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Merrily we roll along pdf
Django Reinhardt's guitar solo on the standard "What Is This Thing Called Love", transcribed from his 1947 recording. In standard notation.Descripción completa
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1. A transparent material along which we can transmit light is called 1.
Fiber optics 2. Flashlight 3. An optic fiber 4. Xenon bulb 2. A simple fiber optic system would consist of 1.
A light source, an optic fiber and a photoelectric cell 2. A laser, an optic fiber and an LED 3. A copper coaxial cable, a laser and a photoelectric cell 4. An LED, a CRT and a light source 3.
Optic fiber is normally made from 1. Coherent glass and xenon 2. Copper 3. Water 4. Silica glass or plastic
4.
The following are the advantages of optical fiber system except 1. Greater capacity 2. Crosstalk immunity 3. Safer to handle 4. Lower initial cost of installation
5.
Plastic fibers have the following advantages over glass fibers except 1. Flexibility 2. Ease of installation 3. Ruggedness 4. Low attenuation
6.
This explains how a light may react when it meets the interface of two transmission materials that have different indices of refraction. 1. Huygens' Law 2. Nyquist's Theorem 3. Snell's Law 4. Quantum Theory
7.
In Optical fibers,
1.
The core and cladding have the same index of refraction 2. The core and cladding have the same area
3.
The core surrounds the cladding 4. The cladding surrounds the core
8. A type of fiber whereby light rays take many paths between the source and the receiver. 1.
Monomode 2. Multimode 3. Single mode 4. Step index
9. A figure of merit used to measure the light gathering or light collection ability of the optical fiber. 1. Acceptance angle 2.
10. The basic optical fiber communications system consists of the following except 1.
Optical source 2. Photodetector 3. Transmission medium 4. 48 v power supply
11. Optical fibers can be made out of 1.
Glass 2. Plastic 3. Combination of both 4. Any of these 12. In ________, the core has an index of refraction that changes continuously from the center to the outside. 1. Step index 2. Graded index 3. Monomode 4. Multimode
13. The following are causes of attenuation and loss of optical power within the fiber except 1.
Microbending loss 2. Connector loss 3. Splicing loss 4. Ohmic loss
14. For a signal to be propagated through the optical fiber, the angle of incidence should be________ the
critical angle. 1. Greater than 2. Less than 3. Equal to 4. None of these
15. A ray of light in a transparent material of refractive index 1.5 is approaching a material with a refractive
index of 1.48. At the boundary, the critical angle is 1. 90 degrees 2. 9.4 degrees 3. 75.2 degrees 4. 80.6 degrees
16. The first material has a refractive index of 1.51 and the angle of incidence is 38 degrees and the second
material has a refractive index of 1.46. What is the angle of refraction? 1. 30.55 degrees 2. 39.55 degrees 3. 75.2 degrees 4. 40.55 degrees
17. If the refractive index of the core of an optic fiber was 1.47 and that of the cladding was 1.44,the cone of
acceptance would have an angle of approximately 1. 17.19 degrees 2. 72.82 degrees 3. 78.4 degrees 4. 34.36 degrees
18. In free space, light travels at approximately 1.
Insufficient stirring of the ingredients during manufacture 2. Changes in the density of the fiber due to uneven rates of cooling 3. Microscopic cracks in the cladding which allow leakage of the vacuum in the core 4. Impurities in the fiber
20. Cleaving is the process of 1.
Removing the cladding before connecting fibers together 2. Cutting the end of the fiber in preparation for connecting two fibers 3. Cleaning the surface of optic fibers 4. Inspecting fibers for flaws
21. A typical value of insertion loss for a mechanical splice 1.
-50 dB 2. 0.2 dB 3. 12 mm 4. 3 dB 22. The speed of light in a transparent material 1. Is always the same regardless of the material chosen 2. Is never greater than the speed of light in free space 3. Increases if the light enters a material with a higher refractive index 4. Is slowed down by a factor of 1 million within the first 60 meters
23. The following are light detectors in fiber optic communications system except 1.
ILD 2. PIN diode 3. APD 4. None of these
24. The following are three distinct regions of an optical fiber except 1.
Core 2. Cladding 3. Jacket 4. Coating
25. The maximum angle in which external light rays may strike the air fiber interface and still propagate
down the fiber 1. Critical angle 2. Acceptance angle 3. Numerical aperture 4. Beamwidth
26. Which of the following combinations is impossible for optical fibers? 1.
Plastic core and cladding 2. Glass core and cladding 3. Plastic core and glass cladding 4. Glass core and plastic cladding
27. The scientist who coined the term "Fiber Optics" 1.
Hopkins 2. Hansel 3. Kapany 4. Van Heel
28. A technology for carrying many signals of different capacities through a synchronous, flexible optical
hierarchy. 1.
PDH 2. SDH 3. SONET 4. ATM
29. Two digital signals whose transmission occur at almost the same rate are 1.
36. Which theory states that light wave behaves as if it consists of many tiny particles? 1.
Huygens' 2. Nyquist's 3. Doppler's 4. Quantum
37. Fiber optic cables operate at frequencies near 1.
20 MHz 2. 200 MHz 3. 2 GHz 4. 800 THz
38. When a beam of light enters one medium from another, which quantity will not change? 1.
Direction 2. Speed 3. Frequency 4. None of these
39. Dispersion caused by the difference in the propagation times of light rays that take different paths down
the fiber.
1.
Material 2. Wavelength 3. Modal 4. Delay
40. A non-coherent light source for optical communications system. 1.
ILD 2. LED 3. APD 4. PIN diode
41. The numerical aperture of a fiber if the angle of acceptance is 15 degrees is 1.
0.17 2. 0.26 3. 0.50 4. 0.75
42. Single frequency light is called 1.
Pure 2. Intense 3. Coherent 4. Monochromatic
43. What is the unit of light wavelength? 1.
Micron 2. Angstrom 3. Mils 4. Fathom
44. A high speed LAN defined by ANSI using fiber optic cables 1.
NTSC 2. SDH 3. FDDI 4. SONET
45. What is the process of using two or more light sources at different wavelengths each separately
modulated with the same fiber? 1. SDH 2. FDM 3. TDM 4. WDM
46. The European standard for synchronous transmission over fiber optic networks. 1.
NTSC 2. SDH 3. FDDI 4. SONET
47. What is the light source typically used in single mode optical fiber? 1.
Phototransistor 2. Laser 3. Photoresistor 4. LED
48. An OTDR is used for 1.
Fault location 2. Splice and connector evaluation 3. Loss per unit length measurement 4. All of these
49. The coupling loss due to angular deviation from the optimum alignment of source to the fiber optic cable 1.
Lateral misalignment 2. Gap misalignment 3. Angular misalignment 4. Numerical aperture loss
50. Which of the following is used to protect the core and the cladding of the fiber? 1.
Insulation 2. Plastic 3. Glass 4. Kevlar strength members
51. Determine the acceptance angle of light passing to a glass having a refractive index of 1.56 to ethyl
having a refractive index of 1.51.
1.
17.7 degrees 2. 21.3 degrees 3. 23 degrees 4. 25 degrees 52. Calculate the energy of the photon of infrared light energy at 1.55 um. 1. 1.28 x 10exp-19 J 2. 1.6 x 10exp19 J 3. 1.22 x 10exp-16 J 4. 1.9 x 10exp-14 J
53. The amount of power per unit area in optical fiber is called 1.
Irradiance 2. Radiance 3. Reflectance 4. Permeance 54. Light at 1.55 um in air has what energy in eV? 1. 1.2 eV 2. 1 eV 3. 0.6 eV 4. 0.8 eV
55. An object farther from a converging lens than its focal point always has an ____ image. 1.
Virtual 2. The same in size 3. Inverted 4. Smaller size
56. What parts of the body are most sensitive to laser damage? 1.
Hair 2. Nails 3. Eye and skin 4. Teeth
57. Who was the first person who actually produced laser light? 1.
Maiman 2. Edison 3. Einstein 4. Volta
58. One of the advantages of fiber optics which is referred to the volume of capacity of signals it can carry. 1.
Security
2.
Weight 3. Bandwidth 4. Physical size
59. 1 micron is equal to _____ meters. 1.
10exp-6 2. 10exp-12 3. 10exp-15 4. 10exp-18
60. The small proportion of light scattered by Rayleigh scattering which is returned towards the source. 1.
Optoscatter 2. Standing waves 3. Return loss 4. Backscatter
61. Dispersion caused by different wavelengths contained in the transmitted light. 1.
Intermodal 2. Chromatic 3. Optical 4. Any of these
62. A ray that always passes through the core axis as it is propagated 1. Axial 2.
Meridional 3. Skew 4. Direct
63. The typical cladding diameter of an optical fiber 1.
8 um 2. 10 to 100 um 3. 125 um 4. 800 to 1550 um
64. The typical core diameter of an optical fiber is 1.
8 um 2. 62.5 um 3. 125 um
4.
800 to 1550 um
65. A reflection that occurs from a surface whenever there is a sudden change in the refractive index at the
end of the fiber. 1. Total internal 2. Reflection loss 3. Fresnel reflection 4. Backscatter
66. The first device used to transmit voice using light as a carrier 1.
