在如图甲所示的电路中,四节干电池串联,小灯泡A、B的规格为“3.8 V,0.3

题型:实验题

问题:

在如图甲所示的电路中,四节干电池串联,小灯泡A、B的规格为“3.8 V,0.3 A”,合上开关S后,无论怎样移动滑动片,A、B灯都不亮.

(1)用多用电表的直流电压挡检查故障.

①选择开关置于下列量程的________挡较为合适(用字母序号表示);

A.2.5 V              B.10 V

C.50 V                 D.250 V

②测得c、d间电压约为6 V,e、f间电压为0,则故障是________;

A.A灯丝断开         B.B灯丝断开

C.d、e间连线断开          D.B灯被短路

(2)接着换用欧姆表的“×1”挡测灯泡的电阻,欧姆表经过欧姆调零.

①测试前,一定要将电路中的开关S________;

②测c、d间和e、f间电阻时,某次测试结果如图乙所示,而根据小灯泡的规格计算出的电阻为12.7Ω,它不等于测量值,原因是:______________.

考点:实验:伏安法测电阻实验:练习使用示波器实验:测绘小灯泡的伏安特性曲线实验:探究影响导体电阻的因素
题型:实验题

宫内节育器的副反应中不正确的是()。

A.月经过多

B.经期延长、周期中点滴出血

C.腰酸

D.下腹坠胀

E.恶心、呕吐

题型:实验题

用标幺值进行短路电流计算时,短路点的计算电压UC=10KV,容量基准值Sd=100MVA,则电流基准值为。()

A.1000A

B.10000A

C.7071A

D.5774A

题型:实验题

钢轨探伤仪0°探头利用的超声波波形是()。

A、纵波

B、横波

C、表面波

D、板波

题型:实验题

( )是代表我国工程咨询业的行业协会。

A.中国工程咨询协会
B.中国国际工程咨询公司
C.会员代表大会
D.常务理事会

题型:实验题

I first went to hear a live rock concert when I was eight years old. My brother and his friends were all fans of a heavy metal group called Black Wednesday. When they discovered that Black Wednesday were going to perform at our local theatre, they all bought (21) for the performance. However, at the last minute, once of the friends couldn’t go, so my brother offered me the ticket. I was really excited!

I remember the buzz (嘈杂声) of excitement inside the theatre as we all found our seats. After a few minutes, the lights went down and everybody became quiet. I could barely make out the stage in the (22) . We waited. Then there was a roar from the crowd, like an explosion, as the first members of the band stepped onto the stage. My brother leaned over and shouted something in my ear, but I couldn’t hear what he was saying. The first song was already starting and the music was as (23) as a jet engine. I could (24) the drum beats and bass notes in my stomach.

I can’t recall any of the songs that the band played. I just (25) that I really enjoyed the show and didn’t want it to (26) . But in the end, after three encores (加演), the show finished. We left the (27) and walked unsteadily out onto the pavement. I felt a little dizzy, as if I had just woken from a long sleep. My ears were still (28) with the beat of the last song.

After the (29) , I became a Black Wednesday fan too for a few years before getting into other kinds of music. Once in a while, though, I listen to one of their songs and (30) I’m back at that first show.

21().

A.flowers 

B.drinks 

C.clothes 

D.tickets

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