如图所示,理想变压器原副线圈匝数之比为4:1,原线圈接入一电压为u=220sin

题型:多选题

问题:

如图所示,理想变压器原副线圈匝数之比为4:1,原线圈接入一电压为u=220sin100πtV的交流电源,副线圈接一个R=27.5Ω的负载电阻.则下述结论正确的是(  )

A.副线圈中电压表的读数为55V

B.副线圈中输出交流电的周期为0.01s

C.原线圈中电流表的读数为0.5A

D.原线圈中的输入功率为110W

考点:变压器的结构和原理
题型:多选题

阅读理解

     Kids are bombarded(攻击) with advertisements from every possible source: boards, clothes, walls, TV, websites

and radios. Often, even though kids don't have their own income yet, this advertising is aimed directly at them.

     Many parents have no idea that their 3-year-old children like McDonald's golden arches. Morns and dads are also

shocked when their 12-year-old children insist on(坚持) having Nike sports shoes. The businessmen give kids the

message: This product is for you. This is what you need. Nothing else will satisfy you.

     How can parents better understand and guard against this?

     Scientists show that children are a rich market for business. How much money is spent on promotion(推销活动)

to children each year? And what are kids spending their money on?

     When finding out what businessmen do to persuade your children to want something, you should know how to

teach your kids the ins and outs of buying and saving. For example, try a couple of family activities, and read through

some helpful tips. Businessmen have more than one way to win a child. Will the world of advertising change for your

child as he or she grows older?

1. Where can kids see or hear the ads?

    ________________________________________________________

2. Why do the businessmen like to spend much on promotions to children?

    ________________________________________________________

3. What will 12-year-old children do after they are bombarded With ads?

    ________________________________________________________

4. What's the message that businessmen give children?

    ________________________________________________________

5. What should parents do to guard against ads?

    ________________________________________________________

题型:多选题

读等高线地形图,回答下列问题。

⑴甲地的海拔高度是___________米。

⑵A—B处的地形________________,丙处的地形是____________。

⑶大青山位于小青_________方位。

⑷大青山与小青山相对高度是____米。

⑸A—B、C—D处可能发育河流的是_________,河流流向________________。

题型:多选题

在△ABC中,∠A=120°,AB=4,AC=2,则tanB的值是_______

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女,27岁,G2PO,孕31周,恶心、呕吐伴不规律下腹坠痛10小时而入院。一般情况尚可,T37.3℃,BP120/80mmHg,P90次/分,R20次/分;心肺未见异常,妊娠腹型,肝脾未及,剑突下右侧轻压痛,无反跳痛,麦氏点无压痛。有不规律宫缩,宫体部无压痛,宫缩间歇期子宫完全松弛。宫高29cm,腹围88cm,LOA,胎心率144次/分,骨盆外测量无异常。肛查:宫颈未消,先露头浮。入院后进行必要的实验室检查如血尿常规检测,请外科会诊,最后诊断为妊娠合并急性阑尾炎。

术中是否置引流()

A.尽可能不放置引流

B.最好短时置盆腔引流

C.最好短时置腹腔引流

D.最好置盆腔引流

E.最好置腹腔引流

题型:多选题

属于萃取塔与蒸馏塔分离原理相同点是()。

A、都是利用组分在另一种介质中溶解度的不同

B、都是利用组分之间相对挥发度的不同

C、都需要控制物料流量及系统压力

D、塔釜都需要加热再沸器

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