Week3TFMCTutor.docx

Week3TFMCTutor.docx

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Week3TFMCTutor

Chapter3

PhysicalLayer

1.

Thephysicallayeristheonlylayerwheretwocommunicatingnodesaredirectlyconnected.

Answer:

TrueDifficulty:

Easy

2.

Aphysicalcircuitreferstothetransmissioncharacteristicsoftheconnection.

Answer:

FalseDifficulty:

Easy

3.

Computersproducedigitaldatawhosevaluesarebinary:

0or1.

Answer:

TrueDifficulty:

Easy

4.

Withmodemcommunications,thereceivingmodemconvertstheincomingdigitalsignalfromthetelephonelineintoananalogsignalthatcanbeunderstoodbythecomputer.

Answer:

FalseDifficulty:

Moderate

5.

Digitaltransmissionproducesmoreerrorsthananalogtransmission.

Answer:

FalseDifficulty:

Easy

6.

Newertelephonecircuits,builtduringthelastdecade,offerhigherqualitybecausetheywerebuiltusinganalogtransmission.

Answer:

FalseDifficulty:

Easy

7.

Inamultipointcircuitconfiguration,eachcomputercanusethecircuitatthesametime.

Answer:

FalseDifficulty:

Easy

8.

Insimplextransmission,thedataflowsinbothdirectionsatthesametime

Answer:

FalseDifficulty:

Easy

9.

Anintercomisanexampleofhalf-duplextransmission.

Answer:

TrueDifficulty:

Moderate

10.

Theamountoftimeittakestoswitchbetweensendingandreceivinginhalf-duplextransmissioniscalledthepropagationdelay.

Answer:

FalseDifficulty:

Easy

11.

Infull-duplextransmission,twostationscansendandreceivesimultaneously.

Answer:

TrueDifficulty:

Easy

12.

Guidedmediareferstothetypeofmediainwhichthemessageisbroadcastthroughtheair.

Answer:

FalseDifficulty:

Easy

13.

Coaxialcablecostslessandofferslessshieldingtoelectricalinterferencethantwistedpaircable.

Answer:

FalseDifficulty:

Moderate

14.

Fiberopticcablecarriessignalsintraditionalelectricalform

Answer:

FalseDifficulty:

Easy

15.

Multimodefiberiscapableoflongertransmissiondistancesthansinglemodefiber.

Answer:

FalseDifficulty:

Easy

16.

Radiodatatransmissionrequiresthateachdevicehasaradioreceiver/transmitterandusesaspecificfrequency.

Answer:

TrueDifficulty:

Moderate

17.

Microwavetransmissionsrequirealineofsightbetweenanytwopoints.

Answer:

TrueDifficulty:

Easy

18.

Propagationdelayisnegligiblewithsatellitetransmission.

Answer:

FalseDifficulty:

Moderate

19.

Oneformofinterferencewithsatellitetransmissioniscalledraindropattenuationinwhichthetransmissionsareabsorbedbyheavyrain.

Answer:

TrueDifficulty:

Moderate

20.

FiberopticcablecanonlybeusedonLANs.

Answer:

FalseDifficulty:

Easy

21.

Radio,infrared,microwaveandsatelliteareallexamplesofguidedmedia.

Answer:

FalseDifficulty:

Moderate

22.

Ofallthemediaavailable,fiberopticprovidesthehighesttransmissionspeeds.

Answer:

TrueDifficulty:

Moderate

23.

Codingschemesaregroupsofbitsthattranslateintothe“alphabet”ofanygivensystem.

Answer:

TrueDifficulty:

Easy

24.

ASCIIistheleastpopularcodefordatacommunications.

Answer:

FalseDifficulty:

Easy

25.

Thepredominantmethodoftransferringinformationinternallyinacomputerisviaparallelmode.

Answer:

TrueDifficulty:

Easy

26.

Serialmodetransmissionismuchfasterthanparallelmodetransmission.

Answer:

FalseDifficulty:

Easy

27.

Ethernet,acommonLANtechnology,usesManchesterencoding..

Answer:

TrueDifficulty:

Easy

28.

Digitaltransmissionoccurswhenthesignalsentoverthetransmissionmediaconstantlyvariesamonganinfinitenumberofstates.

Answer:

FalseDifficulty:

Easy

29.

FrequencyisthenumberofcyclespersecondandisexpressedinHertz.

Answer:

TrueDifficulty:

Easy

30.

Amplitude,frequencyandphaseareallcharacteristicsofasoundwave.

Answer:

TrueDifficulty:

Easy

31.

Frequencymodulationreferstothechangingoftheheightofthesoundwave.

Answer:

FalseDifficulty:

Moderate

32.

Demodulationistheconversationofananalogsignalintoadigitalsignal.

Answer:

TrueDifficulty:

Moderate

33.

“Handshaking”refersthetestingofthecircuittodeterminetheoptimumcombinationofsymbolrateandmodulationtechniquethatwillproducethehighestdatatransmissionrates.

Answer:

TrueDifficulty:

Moderate

34.

Datacompressioncanincreasethethroughputofacommunicationlink.

Answer:

TrueDifficulty:

Easy

35.

Acodecconvertsanincomingdigitalsignaltoananalogsignalfortransmissionoverananalognetwork.

Answer:

FalseDifficulty:

Moderate

36.

Onewaytoreducequantizingerrorsistoincreasethesamplingrateoftheanalogsignal.

Answer:

TrueDifficulty:

Moderate

37.

The“localloop”referstothewiresthatrunfromthecustomerpremisestothetelephoneswitchofthetelephonecompany.

Answer:

TrueDifficulty:

Moderate

38.

Multiplexingincreasesthecostofprovisioningnetworkcircuits.

Answer:

FalseDifficulty:

Moderate

39.

Frequencydivisionmultiplexingdividesthecircuitintoasetofdifferenttimeslots.

Answer:

FalseDifficulty:

Moderate

40.

Timedivisionmultiplexingismoreefficientthatfrequencydivisionmultiplexingbecausetheguardbandsusedinthefrequencydivisionmultiplexingornotneeded.

Answer:

TrueDifficulty:

Moderate

41.

Statisticaltimedivisionmultiplexingdoesnotrequirethecapacityofthecircuittobeequaltothesumofthecombinedcircuits.

Answer:

TrueDifficulty:

Moderate

42.

Wavelengthdivisionmultiplexingcanonlyusedwithcoppercables.

Answer:

FalseDifficulty:

Easy

MULTIPLECHOICE

1.

Dataisphysicallytransmittedfromonecomputerorterminaltoanotherinthe________layer.

a.physical

b.transport

c.application

d.terminal

e.datalink

Answer:

ADifficulty:

Easy

2.

____________referstothetransmissioncharacteristicsofthecircuit.

a.handshaking

b.virtualcircuit

c.bonding

d.logicalcircuit

e.physicalcircuit

Answer:

DDifficulty:

Easy

3.

Twofundamentallydifferenttypesofdataare:

a.DSLandADSL

b.asymmetricandsymmetric

c.MicrosoftandIBM

d.digitalandanalog

e.localareaandwidearea

Answer:

DDifficulty:

Easy

4.

Ingeneral,networksdesignedtotransmitprimarilycomputerdataarelikelytobe________,whilenetworksdesignedtotransmitvoicedataarelikelytobe________.

a.slow,fast

b.level1,level2

c.numeric,musical

d.direct,indirect

e.digital,analog

Answer:

EDifficulty:

Easy

5.

A（n）__________circuitisanothernameforamultipointconfiguration.

a.analog

b.dedicated

c.point-to-point

d.shared

e.simplex

Answer:

DDifficulty:

Moderate

6.

Whichisnottrueaboutpoint-to-pointcircuits?

a.point-to-pointcircuitsarededicatedtotheuseofthetwocomputers.

b.point-to-pointcircuitsaremoreexpensivethanmultipointcircuits.

c.point-to-pointcircuitsarecalleddedicatedcircuits.

d.point-to-pointcircuitsreducetheamountofcablerequiredandusethecircuitmoreefficientlythanmultipointcircuits.

e.Point-to-pointcircuitsareusedwhenthecomputersgenerateenoughtraffictofillthecapacityofthecommunicationcircuit.

Answer:

DDifficulty:

Moderate

7.

Havingaconversationwithsomeoneusingacellularphoneisanexampleof_________transmission.

a.simplex

b.full-duplex

c.half-duplex

d.analog

e.digital

Answer:

BDifficulty:

Easy

8.

Theabilitytotransmitinbothdirections,butonlyinonedirectionatatimeisanexampleof_______________transmission.

a.simplex

b.full-duplex

c.half-duplex

d.analog

e.digital

Answer:

CDifficulty:

Easy

9.

Thetwobasictypesofmediaare:

a.statisticalandfrequency

b.guidedandwireless（radiated）

c.localandwidearea

d.attenuatorandGaussian

e.duplexedandnon-duplexed

Answer:

BDifficulty:

Easy

10.

Thetypeofmediausuallyinstalledonhomesandbusinessesbythetelephonecompanyiscalled____________.

a.fiberopticcable

b.coaxialcable

c.twistedpair

d.phonecable

e.phonewire

Answer:

CDifficulty:

Easy

11.

Theearliesttypeoffiberopticsystemswere:

a.Gradedindexmultimode

b.Attenuated

c.Multimode

d.Singlemode

e.Stepmode

Answer:

CDifficulty:

Easy

12.

Anothertermfortheweakeningofasignaloverdistanceis:

a.turnaroundtime

b.propagationdelay

c.dispersion

d.insulation

e.attenuation

Answer:

EDifficulty:

Moderate

13.

___________referstothespreadingofthesignalthatdifferentpartsofthesignalarriveatdifferenttimesatthedestination.

a.turnaroundtime

b.propagationdelay

c.dispersion

d.insulation

e.attenuation

Answer:

CDifficulty:

Moderate

14.

Whichofthefollowingmediacanbestwithstandharshenvironmentalconditions?

a.shieldedtwistedpair

b.unshieldedtwistedpair

c.Cat5twistedpair

d.coaxialcable

e.fiberopticcable

Answer:

EDifficulty:

Moderate

15.

Microwavetransmission:

a.isatypeofhighfrequencyradiocommunication

b.requiresaclearline-of-sightpath

c.istypicallyusedforlongdistancedatatransmission

d.doesnotrequirethelayingofanycable

e.alloftheabove

Answer:

EDifficulty:

Easy

16.

______________referstothetimeittakesforasignaltotravelfromsendertorecipient（highlyexaggeratedwithsatellitetransmission）.

a.Line-of-sighteffect

b.Multimodeindex

c.Saturationeffect

d.Raindropattenuation

e.Propagationdelay

Answer:

EDifficulty:

Moderate

17.

Whichofthefollowingisnotanimportantfactortoconsiderwhenselectingmediatobeusedinanetwork?

a.prestigevalueofthetypeofmedia

b.typeofnetwork

c.cost

d.transmissiondistance

e.security

Answer:

ADifficulty:

Moderate

18.

Whichofthefollowingmediaistheleastsecure?

a.coaxialcable

b.unshieldedtwistedpair

c.shi