自耦变压器铁芯上只绕有一个线圈,原、副线圈都只取该线圈的某部分,一升压式自耦调压

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问题:

自耦变压器铁芯上只绕有一个线圈,原、副线圈都只取该线圈的某部分,一升压式自耦调压变压器的电路如图所示,其副线圈匝数可调.已知变压器线圈总匝数为1900匝;原线圈为1100匝,接在有效值为220V的交流电源上.当变压器输出电压调至最大时,负载R上的功率为2.0kW.设此时原线圈中电流有效值为I1,负载两端电压的有效值为U2,且变压器是理想的,则U2和I1分别约为(  )

A.380 V和5.3 A

B.380 V和9.1 A

C.240 V和5.3 A

D.240 V和9.1 A

考点:变压器的结构和原理
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B Customs of Bulgaria: Marriage and Family保加利亚习俗:婚姻与家庭
The average age for women to marry is between 18 and 25.25 tend to (1) when somewhat older. A church wedding often (2) the legal civil ceremony, and a large reception, which often involves (3) music and dancing, is held in the evening. Wedding traditions include (4) money on the bride’s dress to represent future prosperity, the groom (5) the bride at her home, and the couple pulling on opposite (6) of a loaf of bread—whoever gets the largest piece will be (7) boss of the family. Honeymoons are a new tradition.
The principle (8) mutual support is valued in the Bulgarian family. The elderly are (9) cared for by their adult children. Unmarried adults live with their (10) and many newly married couples live with one set of parents (11) they are able to get housing of their own. Most families (12) urban areas live in apartments, which are in short
supply, while (13) in rural areas usually have their own houses. Many village houses (14) owned by families who live in urban areas, who use them_ (15) summer and weekend retreats, or for retired parents.
Most families in (16) areas do not have more than two children, while families in (17) areas tend to be larger. Grandparents play an important role in (18) care, particularly in urban areas, where most women work outside the (19) . Men of the younger generation have begun to help with household (20) , once considered only women’s responsibility.

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请你辨析

小亮说:“我长得帅,形象酷,我优秀。”

小强说:“我的学习成绩很棒,我很优秀”

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王安石变法中“市易法”规定:由政府拨出巨款设“市易务”,平价收购商贩不易脱售的货物,等到市场缺货时再卖出去 商贩可向市易务交纳抵押品或成批赊购货物,半年出息一分。下列对“市易法”的看法正确的有

①这是利用封建国家的权力干预经济     ②它限制了大商人控制和操纵市场

③它能稳定物价和调节市场             ④政府能增加国库收入

A.①②

B.①③

C.②③④

D.①②③④

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散水的宽度应根据当地的降雨量.地基土质情况及建筑物来确定,一般在600mm以上,同时应比建筑物挑檐宽度大()mm以上。

A.100

B.200

C.400

D.600

题型:选择题

关于心房颤动的诊断,下列哪项不正确?()

A.心音强弱不等

B.心律绝对不齐

C.容易听到第四心音

D.心率大于脉率

E.心电图P波消失,代之f波

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