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在图甲所示的电路中，闭合电键S后，电压表的示数为3V，两个电流表的指针指在图乙所示的同一位置。则电灯L1中的电流I1＝  （19） A，L1的电阻R1＝ （20）  Ω，电路的总电阻R＝ （21）    Ω；相同时间内电灯L1消耗的电功W1与L2消耗的电功W2之比为  （22）       。

答案

0.21531：4
 

测量灯泡L1电流的量程是0～0.6A，所以电流表示数为0.2A，也就是电灯L1中的电流I1=0.2A，

所以L1的电阻R1==3/0.2=15Ω，

测量总电流的量程是0～3A，所以电流表示数为1A，也就是电路总电流I=1A，

两灯并联，电源电压等于灯泡L1两端电压，U=U1=3V，

所以总电阻R=U/I=3/1=3Ω，

通过灯泡L2的电流I2=I-I1=1A-0.2A=0.8A，

两灯泡消耗的电功率之比 P1：P2=UI1：UI2=0.2A：0.8A=1：4．

单项选择题

For good or ill, globalization has become the economic buzz-word of the 1990s. National economies are undoubtedly becoming steadily more integrated as cross-border flows of trade, investment and financial capital increase. Consumers are buying more foreign goods, a growing number of firms now operate across national borders, and savers are investing more than ever before in far-flung places.

Whether all of this is for good or ill is a topic of heated debate. One positive view is that globalization is an unmixed blessing, with the potential to boost productivity and living standards everywhere. This is because a globally integrated economy can lead to a better division of labor between countries, allowing low-wage countries to specialize in labor-intensive tasks while highwage countries use workers in more productive ways. It will allow firms to exploit bigger economies of scale. And with globalization, capital can be shifted to whatever country offers the most productive investment opportunities, not trapped at home financing projects with poor returns.

Critics of globalization take a gloomier view. They predict that increased competition from low-wage developing countries will destroy jobs and push down wages in today’s rich economies. There will be a race to the bottom as countries reduce wages, taxes, welfare benefits and environmental controls to make themselves more competitive. Pressure to compete will erode the ability of governments to set their own economic policies. The critic also worry about the increased power of financial markets to cause economic havoc, as in the European currency crises of 1992 and 1993, Mexico in 1994～1995 and South-East Asia in 1997.

According to the positive view, globalization can ().

A. allow low-wage countries to use workers in more productive ways

B. help low-wage countries get rid of labor-intensive economy

C. enable firms to exploit bigger economies of scale

D. cause capital to shift to countries where there is greatest fund shortage
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多项选择题

采区回风巷、采掘工作面回风巷风流中瓦斯浓度超过1.0%或二氧化碳浓度超过1.5%时，必须（）。

A、停止工作

B、切断电源

C、撤出人员

D、采取措施

E、进行处理
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