第1题
已知电路如图a所示,R=50Ω,L=10H,US=100V,电感未储能。t=0时,S开关合上,试求iL、uL、uB,并画出其波形
第2题
已知电路如图所示,US=10V,R=4Ω,R1=R2=6Ω,S开关合上前,L与C均未储能,试求S开关合上后,i(0+)、i1(0+)、i2(0+)、uC(0+)、uL(0+)。
第4题
图(a)所示电路为一个标准高压电容器的电路模型,电容C=2μF,漏电阻R=10MΩ。FU为快速熔断器,uS=2300sin(314t+90°)V,t=0时熔断器烧断(瞬间断开)。假设安全电压为50V,问从熔断器熔断之时起,经历了多少时间后,人手触及电容器两端才是安全的?
第5题
图所示电路中,直流电压源的电压US=8V,直流电流源IS=2A,R=2Ω,L=4H。开关S原未接通,L无电流。在t=0时,将开关S接通到位置1;经过1s,将开关S从位置1断开并立即接通到位置2。试求i(t)和u(t)。
第6题
第一节 单项填空
阅读下面的句子和对话,从[A]、[B]、[C]三个选项中选出一个能填入空白处的最佳选项。
Our teacher asked us ______so much noise.
A.not make
B.doesn't make
C.not to make
第7题
A.玩具是影响儿童性格形成的重要因素
B.可以根据儿童的玩具看出儿童的性格
C.儿童的玩具能反映出儿童的心理状态
D.合适的玩具能够塑造儿童良好的性格
第8题
第二节 完型填空
阅读下面短文,从短文后所给的[A]、[B]、[C]三个选项中选择能填入相应空白处的最佳选项。
Many students do not like tostudy history(历史).They say that there are【C1】______ many names and dates to【C2】______ .But if we do not know about the【C3】______ ,we can not understand the present well.For example,if we wish to know how men【C4】______ to use fire,we have to know what men did【C5】______ the past to travel at night or to keep themselves【C6】______ in cold nights.Only a study of history will make US realize(意识到)【C7】______ everything we do today is the result of what【C8】______ people did in the past.
As we【C9】______ history,we learn many interesting【C10】______ .History helps US understand our present life better.
【C1】
A.too
B.enough
C.nearly
第10题
第二节 完型填空
阅读下面短文,从短文后所给的[A]、[B]、[C]三个选项中选择能填入相应空白处的最佳选项。
Many students do not like tostudy history(历史).They say that there are【C1】______ many names and dates to【C2】______ .But if we do not know about the【C3】______ ,we can not understand the present well.For example,if we wish to know how men【C4】______ to use fire,we have to know what men did【C5】______ the past to travel at night or to keep themselves【C6】______ in cold nights.Only a study of history will make US realize(意识到)【C7】______ everything we do today is the result of what【C8】______ people did in the past.
As we【C9】______ history,we learn many interesting【C10】______ .History helps US understand our present life better.
【C1】
A.too
B.enough
C.nearly