问题
选择题
某交流电电源电压的瞬时值表达式为u=6 sinl00πt（V），则下列说法中正确的是（ ）A．用交流电压表测该电源电压时，示数是6V B．用交流电压表测该电源电压时，示数是6 C．用此电源给电磁打点计时器供电时，打点的时间间隔为0.01s D．把标有“6V 3W”的小灯泡接在该电源上时，小灯泡将被烧毁 |
V
答案
答案：A
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| 某交流电电源电压的瞬时值表达式为u=6sinl00πt（V），则下列说法中正确的是（ ） A．用交流电压表测该电源电压时，示数是6V B．用交流电压表测该电源电压时，示数是6 C．用此电源给电磁打点计时器供电时，打点的时间间隔为0.01s D．把标有“6V 3W”的小灯泡接在该电源上时，小灯泡将被烧毁 |
答案：A
| 短文改错。 | |
| The earliest coins in world were used in China from about 650 BC. Coins may be of different in size, weight and shape, and they may be made from different metals, Usually they have different designs on the two sides. There is usually the head of the well known person on one side. Today the coin is marked by the name of the country, the date and its valuable. In the past, many things could be used for money, such like seashells, rings, bamboo sticks, wood and so on. The earliest coin in the west were made of gold, mixed with silver. Much collections of coins were discovered. The largest collection found in Britain contained about 200 000 silver penny that were all over 600 years old. | 1.____ |