# Computer-Computer Networks MCQs Set/4 Sample Test,Sample questions

## Question: ``` Practical pulse broadening value for graded index fiber lies in the range of __________ ```

1.0.9 to 1.2 ns/km

2.0.2 to 1 ns/km

3.0.23 to 5 ns/km

4.0.45 to 8 ns/km

1.M-ary PSK

2.MFSK

4.DFSK

1.0.173 Î¼sec

2.0.152 Î¼sec

3.0.96 Î¼sec

4.0.121 Î¼sec

1.True

2.False

## Question: ```A device that reduces the intensity of light in optical fiber communications is ___________ ```

1.compressor

2.Optical attenuator

3.Barometer

4.Reducer

1.30.46ns/km

2.31.23ns/km

3.28.12ns/km

4.26.10ns/km

1.92.6 ns

2.86.7 ns

3.69.3 ns

4.68.32 ns

## Question: ```After Total Internal Reflection the Meridional ray __________ ```

1.Makes an angle equal to acceptance angle with the axial ray

2.Makes an angle equal to critical angle with the axial ray

3.Travels parallel equal to critical angle with the axial ray

4.Makes an angle equal to critical angle with the axial ray

1.Half

2.Quarter

3.One-third

4.Twice

1.0.2 and 0.9Î¼m

2.0.1 and 0.2Î¼m

3.1.3 and 1.6Î¼m

4.2 and 3Î¼m

## Question: ```An optical fiber behaves as a birefringence medium due to differences in ___________ ```

1.Effective R-I and core geometry

3.Transmission/propagation time of waves

4.Refractive indices of glass and silica

1.69.8

2.99.86

3.73.2

4.104.66

1.1.00Î¼sec

2.0.06Î¼sec

3.0.90Î¼sec

4.0.30Î¼sec

1.True

2.False

1.True

2.False

## Question: ```Dispersion-shifted single mode fibers are created by __________ ```

1.Increasing fiber core diameter and decreasing fractional index difference

2.Decreasing fiber core diameter and decreasing fractional index difference

3.Decreasing fiber core diameter and increasing fractional index difference

4.Increasing fiber core diameter and increasing fractional index difference

## Question: ```Disturbance along the fiber such as vibrations, discontinuities, connectors, splices, source/detectors coupling result in __________ ```

1.Modal noise

2.Inter-symbol interference

3.Infrared interference

1.False

2.True

1.18.23ns/km

2.20.15ns/km

3.26.93ns/km

4.10.23ns/km

1.FSK

2. DSK

3.PSK

1.True

2.False

## Question: ```For suitable power confinement of fundamental mode, the normalized frequency v should be maintained in the range 1.5 to 2.4Î¼m and the fractional index difference must be linearly increased as a square function while the core diameter is linearly reduced to keep v constant. This confinement is achieved by? ```

1.Increasing level of silica doping in fiber core

2.Increasing level of germanium doping in fiber core

3.Decreasing level of silica germanium in fiber core

4.Decreasing level of silica doping in fiber core

1.15.23dB

2.16.98dB

3.17.12dB

4.16.62dB

1.Air

2.Silica

3.Water

4.Plasma

1.True

2. False

## Question: ```Intermodal dispersion occurring in a large amount in multimode step index fiber results in ____________ ```

1.Propagation of the fiber

2.Propagating through the fiber

4.Attenuation of waves

1.0.1dB/km

2.0.2dB/km

3.0.3dB/km

4.0.4dB/km

1.True

2.False

1.True

2.False

1.True

2.False

## Question: ```Photonic crystal fibers also called as ___________ ```

1.Conventional fibers

2.Dotted fibers

3.Stripped fibers

4.Holey fibers

2.Improve

3.Reduce

4.Attenuate

1.True

2.False

## Question: ```The digital transmission on implementation of polarization modulation which involves polarization characteristics of the transmitted optical signal is known as _____________ ```

1.Frequency shift keying

2.Amplitude shift keying

3.Phase shift keying

4.Polarization shift keying

## Question: ```The fibers which relax the spectral requirements for optical sources and allow flexible wavelength division multiplying are known as __________ ```

1.Dispersion-flattened single mode fiber

2.Dispersion-enhanced single mode fiber

3.Dispersion-compressed single mode fiber

4.Dispersion-standardized single mode fiber

1.Less than 1Î¼m

2.More than 5Î¼m

3.More than 3Î¼m

4.More than 2Î¼m

1.8%

2.2 to 8%

3.10 t0 50%

4.70%

## Question: ```The modal noise can be reduced by __________ ```

1.Decreasing width of signal longitudinal mode

2.Increasing coherence time

3.Decreasing number of longitudinal modes

4.Using fiber with large numerical aperture

1.Î´f>>1/Î´T

2.Î´f=1/Î´T

3.Î´f<<1/Î´T

4.Negligible

1.Scattering

2.Attenuation

3.Absorption

4. Refraction

1.IR sensors

2.Photodiodes

3.Zener diodes

4.Transistors

## Question: ```The periodic arrangement of cladding air holes in photonic band gap fibers provides for the formation of a photonic band gap in the ___________ ```

1.H-plane of fiber

2.E-plane of fiber

3.E-H-plane of fiber

4.Transverse plane of fiber

## Question: ```The signals which are obtained by encoding each quantized signal into a digital word is called as ```

1.PAM signal

2.PCM signal

3.FM signal

4.Sampling and quantization

## Question: ```The variant of non-zero-dispersion-shifted fiber is called as __________ ```

1.Dispersion flattened fiber

2.Zero-dispersion fiber

3.Positive-dispersion fiber

4.Negative-dispersion fiber

1.3dB/km

2.2dB/km

3. 1dB/km

4.4dB/km

1.km

2.dB

3.dB/km

4.Coulombâ€™s

1.FSK

2.DSK

3.PSK

1.MFSK

2.MDSK

3.MPSK

## Question: ```_____________ is essentially a crude form of Amplitude shift keying. ```

1.Analog modulation

2.Digital intensity modulation

3.Photodetector

1.FSK

2.DSK

3.PSK