问题 选择题

一只电饭煲和一台洗衣机并联接在输出电压u=311sin314tV的交流电源上(其内电阻可忽略不计),均正常工作。用电流表分别测得通过电饭煲的电流是5.0A,通过洗衣机电动机的电流是0.50A,则下列说法中正确的是(    )

A.电饭煲的电阻为44Ω,洗衣机电动机线圈的电阻为440Ω

B.电饭煲消耗的电功率为1555W,洗衣机电动机消耗的电功率为155.5W

C.1min内电饭煲消耗的电能为6.6×104J,洗衣机电动机消耗的电能为6.6×103J

D.电饭煲发热功率是洗衣机电动机发热功率的10倍

答案

答案:C

交流电压有效值是,电饭煲是纯电阻,用来加热的,电阻,洗衣机的电机是非纯电阻电路,所以不能用欧姆定律。A错。

电饭煲消耗的电功率;

洗衣机电动机消耗的电功率,B错;

1min内消耗的电能:电饭煲为

洗衣机电动机消耗的=6.6×103J,C对;

洗衣机是用来对外做功也有自身发热,所以洗衣机发热功率小于6.6×103J小于电饭煲电动机发热功率的10倍,D错。

完形填空
About one year ago, a couple with three children moved into the apartment next door to me. I never heard any noise form the children, but I often heard the parents     shouting at the kids, not in a nice tone, but in a (n)     one.
We often     in the hallway. I always greeted them,     the only answer I ever got was a “hello” from the eight-year-old girl. I usually     to see my doctor and one day when I returned they were just     their apartment and the little girl was     the outside door open for the others. I     in the car doing     things because I wasn’t eager to be snubbed (冷落) again. Finally I got out of my car and walked towards the door. The parents were telling her to     to get into the car, but the little girl was still holding the door,     me! I hurried although I was still in pain from my injury.
I forgot to tell her how     I was for her kindness. I wrote a note saying how much her act of kindness had     an old man’s heart.
The next day there was a (n)     on my door and it was the little girl and her father. She was quite     of her behavior and thanked me. Then I noticed her mother was there, too. Her parents     me, too.
Now when we meet in the hall way we always greet each other, in a friendly     .
Last night there was a heavy snow. I looked out at my car and     how I was going to keep my doctor’s     because I could only walk for a short time. This morning when I opened the front door, all the snow was removed.
Isn’t it     that the small kind act of an 8-year-old girl can change so many things for the better? It is said that good tings come from small acts.
小题1:
A.quietly B.strangelyC.quicklyD.angrily
小题2:
A.frighteningB.exciting C.sincereD.kind
小题3:
A.quarreledB.metC.chattedD.argued
小题4:
A.whenB.so C.butD.or
小题5:
A.went outB.set outC.took out D.gave out
小题6:
A.decoratingB.cleaning C.returning D.leaving
小题7:
A.breakingB.operatingC.holdingD.unlocking
小题8:
A.keptB.remained C.insistedD.left
小题9:
A.favoriteB.importantC.unnecessaryD.curious
小题10:
A.hurryB.driveC.stayD.greet
小题11:
A.hunting forB.asking for C.waiting forD.calling for
小题12:
A.beneficialB.influentialC.anxiousD.grateful
小题13:
A.strengthenedB.brokenC.touchedD.saved
小题14:
A.noteB.knockC.invitationD.picture
小题15:
A.proudB.awareC.afraidD.sure
小题16:
A.understoodB.recognizedC.praisedD.thanked
小题17:
A.manner B.appearanceC.statement D.announcement
小题18:
A.foundB.doubtedC.rememberedD.wondered
小题19:
A.advice B.appointmentC.suggestionD.attention
小题20:
A.amazingB.confusingC.disappointingD.challenging
填空题