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LT4.3 ElectricCurrentinCircuitsClassno._____Name:_____________________________________Section___________Date________

A. Writetheletterofthecorrectanswer,inCAPITAL,onthespacebeforeeachnumber.Inthefigurebelow,three

bulbsareconnectedin

serieswitha12Vsource.

1. Ifthethreebulbsareidenticalthetotal

voltageis

A. ThesumofindividualvoltagedropsB. OnethirdofthevoltagesupplyC. Threetimesthevoltagesupply

2. Iftheresistanceofbulb1is10,bulb2is15,andbulb3is20,thetotalresistanceis

A. 4.6 B.15 C.45 D.903.

If

the

resistance

of

bulb

1

is

10

,

bulb

2

is

15,andbulb3is20,thetotalcurrentis

A. 3.75A B.2.61A C.0.80A D.0.27A4. Iftheresistanceofbulb1is10,bulb2is15,andbulb3is20,whichonereceives

thebiggestcurrent?

A. bulb1 C.bulb3B. bulb2 D.sameforall

5. Whenwecallacircuitaclosedcircuitwemean

A. ThecurrentisblockedandcannotflowB. Thereisonlyonepathforcurrenttoflowthrough

C. Thepathwayiscompletewithnogapandcurrentcanflow

D. Thereisonlyonedeviceconnectedtothepowersource.

6. Whentwolinesareconnectedinseries,whichistrue?

A. Thecurrentthroughbothisthesame.B. Thecurrentthroughoneplusthecurrentthroughoneequalsthelinecurrent.

C. Togethertheyhavelessresistancethaneitherwouldalone.

D. Thereisdangeroroverloadingthecircuit7. Whentwolightbulbsareconnectedinparallel,whichistrue?

A. Thetotalresistanceislessthantheresistanceofeitherbulbalone.

B. Thevoltageprovidedbythebatteryissplitevenlybyeachbulb.

C. Ifonebulbburnsouttheotherbulbwillnotlight.

D. Theindividualresistanceaddsuptomake

the

total

resistance

of

the

line.

8. Ifseveralresistorsareconnectedinparallel,whatdoweknowaboutthetotalresistance?

A. Itisthesumofindividualresistance.B. Thetotalhasavaluelowerthananyotherindividualresistors.

C. Thetotalisgreaterthananyoftheoriginalresistor.

9. Whenyouadddevicestoaseriescircuit,whatdoyouknowaboutthecurrent?

A. Addingmoredevicesincreasestheamountofcurrentthroughthebattery

B. Addingmoredevicesdecreasestheamountofcurrentthroughthebattery.

C. Moredeviceschangetheresistanceofthecircuit,butnotcurrent.

D. Moredevicesincreasethevoltagesuppliedbythebatterytothecircuit.

10.Whenyouadddevicestoaparallelcircuit,whatdoyouknowaboutthecurrent?

A. Thetotalcurrentgetslargerwhendevicesare

added.

B. Theadditionaldevicereceiveslessamountofcurrent.

C. Thetotalcurrentisdecreasedasdevicesareadded.

11. Inaparallelcircuit,A. thecurrentthrougheachbranchisalwaysthesame.

B. thevoltageacrosseachbranchisalwaysthesame.

C. theresistanceacrosseachbranchshouldalwaysbethesame.

D. thegreaterthebranchthegreateristheresistance.

12. Twolightsofdifferentresistancesarewiredinparallel,whichwillburnbrighter?

A. Thelowresistancebulbbecauseitdrawsmorecurrent.

B. Thehighresistancebulb,becauseitdrawsmorecurrent.

C. Thecurrentineachbranchofthecircuitisthesamesotheybrightequally

13.Whichofthefollowingfilamentswoulddrawthemostcurrentiftheyaremadeofthesamematerial?(thickfilamentshavelowerresistancethanthinones,andlongfilamentshavehigherresistancethanshortones)A. along,thinfilamentB. along,thickfilamentC. ashort,thickfilamentD. ashort,thinfilament

14. Howmany6ohmsresistorsinparallelwouldittaketomakearesistanceof2ohms

A. 6 B.4 C.3 D.215.

How

many

6

ohms

resistors

in

parallel

would

ittaketomakearesistanceof1ohm

A. 6 C.3B. 4 D.2

16. A40wattlightbulbisconnectedtoa9voltbattery.Whenanother40Wbulbisconnected

inparallelwiththefirst,whathappenstothe

outputenergyinthebattery?

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LTG101213_Circuits2/2

A. Theoutputenergyremainsunchangedbecausethecircuitisparallelandtheline

currentremainsunchangedbyadditional

devices.

B. Thesecondbulbdrawsmuchcurrentasthefirst,sothecurrentthroughand

energyoutputofthebatterydouble.

C. Thesecondbulbwilldoubletheresistance,thereforehalvethecurrentand

energyoutput.

17. Two4ohmandone2ohmresistorsarewiredinparallel.Whatistheequivalentresistance?

A. 10ohms C.2ohmsB. 6ohms D.1ohm

18. One10ohmresistorisinserieswithanotherresistoranda20vbattery.Ifthecurrentinthe

circuitis2/3ofanamp,whatisthevalueof

thesecondresistor?

A. 10ohms C.30ohmsB. 20ohms

19. Twoidenticalresistorsareconnectedinseries.Thecurrentthroughthecircuitis1.5

ampsandthebatteryvoltageis6volts.What

isthevalueofoneoftheresistors?A. 4ohms C.1ohmsB. 2ohms

20. Comparedwiththecurrentinthewhitehotfilamentofacommonlamp,thecurrentinthe

connectingwireis

A. less C.thesameB. more D.cantbedetermined

B. 120voltsinimpressedinthecomplexcircuitbelow.Eachresistorinthediagramhasaresistanceof10.CompletethetablebelowandshowyoursolutiononaseparatesheetofCLEANpaperneatlyandsystematically.

Resistor Resistance, Current,A Voltage,V

R1 10 4.8 48

R2 10 2.4 24

R3 10 2.4 24

R4 10 4.8 48

R5 10 4 40

R6 10 4 40

R7 10 4 40

R8 10 4 40

R9 10 4 40

R10 10 4 40

R11 10 4 40

R12 10 4 40

R13 10 4 40