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问题 计算题

把一个阻值为10欧姆的电阻R1，与另一个电阻R2串联后接入电路．已知电源电压是12伏特，R2两端的电压是9伏特．求：

（1）通过R1的电流强度；

（2）R2的阻值．

答案

（1）R1两端的电压：U1=U﹣U2=12V﹣9V=3V，

          通过R1的电流：I1===0.3A．

（2）因为两电阻串联，所以电流相等，即I2=I1所以R2的阻值：R2===30Ω．

选择题

下列对静止的看法正确的是 [ ]

A．静止是绝对的不动，是运动的特殊状态

B．静止不是绝对的不动，是一种不显著的运动，是运动的特殊状态

C．静止是运动的特殊状态，是无条件的、相对的运动

D．静止在一定条件下，可以是指永恒不动

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问答题

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