电力与能源——电力系统的当前、潜力差异及电气充电.docx

CaldervaleHighSchool

National45Physics

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ElectricityandEnergyHomework

Homework1.-Current,PotentialDifferenceandElectricalCharge

Statethesymbol,thecorrectunitandtheshortenedformoftheunitintheappropriatecolumnsforeachofthequantitieslisted.Thefirstonehasbeendoneforyou.

Quantity

Quantity

Symbol

Unit

UnitSymbol

time

t

second

s

current

voltage

(2)

Whatisanelectriccurrent? (1)

(a) Calculatethechargethatpassesalongawireifacurrentof10Aflowsfor30seconds. (3)

(b) Calculatethechargethatpassesthroughabulbifitdrawsacurrentof500mAfor8seconds. (3)

(c) 12Coulombspassthroughalampin6seconds.Whatisthecurrentflowingthroughthelamp? (3)

Whatisthedefinitionofthevoltageofasupply? (1)

Drawtheelectricfieldaroundthefollowingcharges.Youmustshowthedirectionofthefieldclearly. (4)

+

+

-

+-

+

-

Lookatthefollowingdiagram.

300V

300V

100V

Whatisthepotentialdifferencebetweenthetwoplates? (1)

7. Sketchthepathswhich (a) anα-particle,

(b) aβ-particle,

and (c) aneutron,

wouldfollowifeachparticleenteredthegivenelectricfieldwiththesamevelocity. (2)

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Pathofparticle

Pathofparticle

Total20marks

Homework2.-ACDC

Explainwhatalternatingcurrentanddirectcurrentmean,andstatethetypeofsupply(mainsorbattery)thatproduceseach. (3)

State:

(a) thevalueofthemainsvoltageinScotland?

(b) thefrequencyofthemainssupply? (2)

Lookatthisoscilloscopepattern:

Isthistracerepresentinga.c.ord.c.input? (1)

(b) Ifthegainissetat1.5Vperdivision,whatisthepeakvoltageofthetrace? (1)

(c) Describewhatwouldhappentothetraceonthescreenifa3Vsourcewasusedinstead.Usethewordsfrequencyandamplitudeinyouranswer. (2)

Howdoesthepeakvalueofanalternatingvoltagecomparetoitsquotedvalue? (1)

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