B 10.A 11.A 12.B 查看更多

 

题目列表(包括答案和解析)

(10·百色)2009年12月11日,为纪念百色起义80周年,百色市森林广场上锣鼓喧天,群众载歌载舞,热闹非凡。下列有关声知识说法正确的是:(    )

A.锣声鼓声都是由锣鼓振动发声的

B.锣声鼓声是通过响度分辨出来的

C.锣鼓声响彻云霄是因为它们的音调高

D.在空气中锣声的传播速度比鼓声的传播速度快

查看答案和解析>>

如图A“观察水的沸腾”的实验探究的是:水沸腾时的现象和水沸腾的温度.图B是实验过程某一时刻的温度,此时水温是
85
85
℃.图甲、乙、丙是三位同学作出的水沸腾的图象,其中正确的是
图.

小刚同学按实验步骤进行了正确的操作,他得出的实验数据如下表所示:
时间/min 9 10 11 12 13 14 15
水温/°C 95 96 97 98 98 98 98
(1)从记录数据可得出结论是:此时水沸腾的温度是
98
98
℃.
(2)小刚发现从开始加热到沸腾的这段时间过长,造成这种现象的原因可能是(给出一种原因即可),解决的办法是
加大酒精灯火焰(或减少烧杯中水的质量)
加大酒精灯火焰(或减少烧杯中水的质量)

查看答案和解析>>

在图11(a)所示的电路中,电源电压为12伏且不变。电阻R1的阻值为30欧,滑动变阻器R2上标有“50W  1A”字样。闭合电键S,电路正常工作。

①求通过电阻R1的电流。

②求变阻器R2消耗的最大功率。

③现用定值电阻来替换电阻R1。要求:选择合适的电表量程,闭合电键,移动变阻器滑片P,能使电流表A1与A2的指针偏离零刻度线的角度恰好相同,如图11(b)所示,且电路能正常工作。

Ⅰ 选用阻值为10欧的定值电阻      满足上述要求(选填“能”或“不能”)。

Ⅱ 求出符合上述要求的定值电阻的阻值范围。(写出计算过程)

 

查看答案和解析>>

在图11(a)所示的电路中,电源电压为12伏且不变。电阻R1的阻值为30欧,滑动变阻器R2上标有“50W  1A”字样。闭合电键S,电路正常工作。

①求通过电阻R1的电流。
②求变阻器R2消耗的最大功率。
③现用定值电阻来替换电阻R1。要求:选择合适的电表量程,闭合电键,移动变阻器滑片P,能使电流表A1与A2的指针偏离零刻度线的角度恰好相同,如图11(b)所示,且电路能正常工作。
Ⅰ 选用阻值为10欧的定值电阻      满足上述要求(选填“能”或“不能”)。
Ⅱ 求出符合上述要求的定值电阻的阻值范围。(写出计算过程)

查看答案和解析>>

There was a boy who was sent by his parents to a boarding school (寄宿学校).   36   being sent away, this boy was the   37   student in his class. He was at the top in every   38   always with high marks.
But the boy changed after   39   home and attending the boarding school. His grades started   40  . He hated being in a   41  . He was lonely all the time. And there were especially dark times when he   42   committing suicide (自杀). All of this was because he felt   43   and no one loved him.
His parents started   44   about the boy. But they even did not know what was   45   with him. So his dad decided to travel to the boarding school and   46   him.
They sat on the bank of the lake near the school. The father started asking him some casual questions about his classes, teachers and   47  . After some time his dad said, “Do you know, son, why I am here today?”
The boy answered back, “To   48   my grades?”
“No, no,” his dad replied. “I am here to tell you that you are the most   49   person for me. I want to see you   50  . I don’t care about grades. I care about you. I care about your happiness. YOU ARE MY LIFE.”
These words   51   the boy’s eyes to be filled with tears. He   52   his dad. They didn’t say anything to each other for a long time.
Now the boy had   53   he wanted. He knew there was someone on this earth who cared for him deeply. He   54   the world to someone. And today this young man is in college at the top of his class and no one has ever seen him   55  !
【小题1】
A.AfterB.BeforeC.WhenD.While
【小题2】
A.hardestB.naughtiestC.brightestD.dullest
【小题3】
A.examB.activityC.gameD.class
【小题4】
A.comingB.returningC.leavingD.reaching
【小题5】
A.risingB.increasingC.reducingD.dropping
【小题6】
A.groupB.termC.company D.party
【小题7】
A.led toB.felt likeC.thought backD.looked for
【小题8】
A.worthless B.carelessC.concernedD.annoyed
【小题9】
A.caringB.turningC.worryingD.speaking
【小题10】
A.crazyB.trueC.possibleD.wrong
【小题11】
A.talk withB.listen toC.tell toD.care about
【小题12】
A.familyB.friendsC.studyD.grades
【小题13】
A.realizeB.analyzeC.checkD.test
【小题14】
A.outstandingB.importantC.famousD.familiar
【小题15】
A.happyB.excellentC.interestedD.satisfied
【小题16】
A.causedB.wantedC.encouragedD.forced
【小题17】
A.answeredB.ignoredC.hatedD.hugged
【小题18】
A.nothingB.somethingC.everythingD.anything
【小题19】
A.showedB.meant C.intendedD.expressed
【小题20】
A.sadB.angryC.pleasantD.joyful

查看答案和解析>>


同步练习册答案