专业英语复习题

《专业英语复习题》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、1、Chargeisanelectricalpropertyoftheatomicparticlesofwhichmatterconsists,measuredincoulombs。2、Wealsoknowthatthechargeeonanelectronisnegativeandequalinmagnitudeto1.60210×10--19Cwhileaprotoncarriesapositivechargeofthesamemagnitudeastheelectron3.、Auniquefeatureofelectricchargeorelectri

2、cityisthefactthatitismobile;thatis,itcanbetransferredfromoneplacetoanother,whereitcanbeconvertedtoanotherformofenergy.4、Althoughwenowknowthatcurrentinmetallicconductorsisduetonegativelychargedelectrons,wewillfollowtheuniversallyacceptedconventionthatcurrentisthenetflowofpositivecha

3、rges.5、ThewaywedefinecurrentasiinEq.(1-l)suggeststhatcurrentneednotbeaconstant-valuedfunction,chargecanvarywithtimeinseveralwaysthatmayberepresentedbydifferentkindsofmathematicalfunctions.6、Thevoltageuabbetweentwopointsaandbinanelectriccircuitistheenergy(orwork)neededtomoveaunitcha

4、rgefromatob。7、Thepowerabsorbedorsuppliedbyanelementistheproductofthevoltageacrosstheelementandthecurrentthroughit.8、Anidealindependentsourceisanactiveelementthatprovidesaspecifiedvoltageorcurrentthatiscompletelyindependentofothercircuitvariables.9、Thesymbolforavoltagesourcehavinguv

5、oltsacrossitsterminalsisshowninFig.1-4(a).10、Anothersymbolthatisoftenusedforaconstantvoltagesource,suchasabatterywithUvoltsacrossitsterminals,isshowninFig.1-4(b).11、WemightobserveatthispointthatthepolaritymarksonFig.1-4(b)areredundantsincethepolaritycouldbedefinedbythepositionsofth

6、elongerandshorterlines.12、Thusifuisthevoltageacrossthesourceanditscurrentiisdirectedoutofthepositiveterminal,thenthesourceisdeliveringpower,givenbyp=ui,totheexternalcircuit.13、Sincethecontrolofthedependentsourceisachievedbyavoltageorcurrentofsomeotherelementinthecircuit,andthesourc

7、ecanbevoltageorcurrent,itfollowsthattherearefourpossibletypesofdependentsources,namely:14、Itshouldbenotedthatanidealvoltagesource(dependentorindependent)willproduceanycurrentrequiredtoensurethattheterminalvoltageisasstated,whereasanidealcurrentsourcewillproducethenecessaryvoltageto

8、ensurethestatedcurrentflow