某同学准备测定一只量程已知的电压表的内阻．器材如下：

A．待测电压表V（量程3V，内阻未知）

B．定值电阻R₀（阻值2KΩ，额定电流50mA）

C．多用电表

D．直流电源E（电动势小于3V，内阻不计）

E．单刀双掷开关S

F．导线若干

该同学利用上述所给的器材，进行如下操作：

①用多用电表进行粗测：该同学选择×100Ω倍率，用正确的操作方法测量，刻度盘上的指针如图1所示，那么测量结果是______Ω．

②为了更准确地测量这只电压表的阻值，该同学已连接好实验电路如图2示，请你帮他写出测量步骤：

a．______；

b．______．

③利用已知和所测的物理量表示电压表的内阻，其表达式为______．

Most "unassertive" people are not confident and take no for an answer much too easily. There is a growing awareness in our society that this tendency (1) the rights of large numbers of people. For example, in recent years there has been an upsurge in (2) and pressure groups. This is a (3) as there will always be a need for such organizations to (4) individuals and minorities in a competitive society. The danger is that we (5) for our rights and lose the art of asserting ourselves. It is better for (6) with other people if you can learn (7) for yourself.
Now, we have to learn to ignore some of the (8) that may be ringing in our unconscious minds, such as: "If you ask once more, I’ll flatten you", and " (9) ".
The main technique that we use in (10) to practice the art of persistence is called Broken Record. (11) we hear one sentence over and over again until we reach screaming pitch and (12) .
Broken Record is the skill of being able to repeat over and over again, (13) , what it is you want or need, until the other person gives in or (14) .
Now, this technique is extremely useful for dealing with situations where your rights are clearly (15) , or coping with situations where you are likely to be diverted by clever, (16) .
The beauty of using Broken Record is that you (17) because you know exactly what you are going to say, however (18) the other person tries to be.
As with most assertive techniques, it must be used appropriately. It is (19) and is not designed to foster deep, interesting conversations and friendships with people! It is primarily of use in situations where (20) .