如图所示，ab=25cm、ad=20cm，匝数为50匝的矩形线圈。线圈电阻r=1

发布时间：2017-06-22 01:39 │ 来源：www.tikuol.com

题型：计算题

问题：

如图所示，ab=25cm、ad=20cm，匝数为50匝的矩形线圈。线圈电阻r=1Ω、外电路电阻R=9Ω，磁感应强度B=0.4T。线圈绕垂直于磁感线的OO'轴以角速度50rad/s匀速转动。求：

（1）从此位置开始计时，它的感应电动势的瞬时值表达式；

（2）1min内R上消耗的电能；

（3）外力对线圈做功的功率；

（4）线圈由如图位置转过30°的过程中，R的电量为多少？

考点：感应电动势电功电功率

题型：计算题

Questions 29-40
· Read the information about the communication of information in business.
· Choose the correct word to fill each gap from A, B or C.
· For each question (29-40) mark one letter A, B or C on your Answer Sheet.

A number of business people still believe that information is power and constantly question how (29) people need to know. As a result, they tell employees (30) as much as they think is essential (31) them to do particular jobs. Furthermore, (32) business people have been taught (33) to communicate effectively and (34) they communicate very badly at all levels.
Recent research shows that (35) most serious problems experienced by modern business are communication (36) Research has also shown that there is a clear link (37) good communication in a business and the motivation of the employees.
Newsletters and notices are not (38) It is the attitude and behavior of business managers which (39) all the difference. Unfortunately, at present, a lot of employees do not believe all the information they receive from their managers (40) they feel that the managers themselves are out of touch with their staff.

A．

B．

C．

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(4分)某校化学兴趣小组的同学为了制取氢氧化镁，他们取9.5g氯化镁固体全部溶解在40.5g水中制成不饱和溶液，然后向其中加入55.8g某溶质质量分数的氢氧化钠溶液恰好完全反应。请计算：

(1)制得的氢氧化镁的质量。

(2)反应后所得溶液中溶质的质量分数。

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题型：计算题

下列关于基本存款账户的说法，正确的是()

A．存款人可以没有基本存款账户，但一定要有一般存款账户

B．存款人可以没有基本存款账户，但一定要有临时存款账户

C．基本存款账户是存款人的非主办账户

D．基本存款账户是存款人的主办账户

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题型：计算题

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A．以盈余公积弥补亏损

B．以资本公积转增资本

C．发放现金股利

D．分派股票股利

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