如图所示,理想变压器的原副线圈匝数比n1:n2=1:10,副线圈与阻值R=20Ω

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问题:

如图所示,理想变压器的原副线圈匝数比n1:n2=1:10,副线圈与阻值R=20Ω的电阻相连.原线圈两端所加的电压u=20sin20πt(V),则(  )

A.副线圈输出交流电的频率为10Hz

B.交流电压表的示数为20V

C.电阻R上消耗的电功率为2kW

D.原线圈中电流的最大值为100A

考点:变压器的结构和原理
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写出本课所学声母,并写出它们的笔顺。

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化简:(1)3a+2-4a-5;(2)2(x2+3)-(5-x2

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中国人民银行决定最低首付款比例为( )。

A.10%

B.20%

C.30%

D.40%

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The China boom is by now a well-documented phenomenon. Who hasn’t (1) the Middle Kingdom’s astounding economic growth (8 percent annually), its mesmerizing (2) market (1.2 billion people), the investment ardor of foreign suitors ($40 billion in foreign direct investment last year (3) ) China is an economic juggernaut. (4) Nicholas Lardy of the Brookings Institution, a Washington D. C.-based think tank,

" No country has (5) its foreign trade as fast as China over the last 20 years. Japan (6) its foreign trade over a 20-year period; China’s foreign trade as quintupled. They’ve become the pre-eminent producer of labor-intensive (7) goods in the world " . But there’s been (8) from the dazzling China growth story—namely, the Chinese multinational. No major Chinese companies have (9) established themselves, or their brands, (10) the global stage. But as Haier shows, that is starting to change. (11) 100 years of poverty and chaos, of being overshadowed by foreign countries and multinationals, Chinese industrial companies are starting to (12) on the world.A new generation of large and credible firms has (13) in China in the electronics, appliance and even high-tech sectors. Some have reached critical mass on the mainland and are now (14) new outlets for their production—through exports and by building Chinese factories abroad, chiefly in Southeast Asia. One example: China’s investment in Malaysia (15) from $8 million in 2000 to $766 million in the first half of this year. (16) China’s export prowess, it will be years (17) Chinese firms achieve the managerial and operational expertise of Western and Japanese multinationals. For one thing, many of its best companies are still at least partially state-owned. (18) , China has a shortage of managerial talent and little notion of marketing and brand-building. Its companies are also (19) by the country’s long tradition of central planning, inefficient use of capital and antiquated distribution system, (20) makes building national companies a challenge.

(12)处填()

A. make a call

B.make a cry

C. make a mark

D.make a voice

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(),毛 * * * * 、朱德总司令发布《向全国进军的命令》,号召全军指战员奋勇前进,坚决、彻底、干净、全部地歼灭中国境内一切敢于抵抗的国民党反动派。

A.1949年3月

B.1949年4月

C.1949年5月

D.1949年6月

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