题干

如图所示,图线Ⅰ为一电源的路端电压随电流变化的图线,图线Ⅱ为一导体两端电压和导体中电流的关系图线,若该导体和电源连接成闭合电路,求路端电压和电源的输出功率.

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解:根据闭合电路欧姆定律U=E﹣Ir可知,当I=0时,U=E,则由图线Ⅰ与纵轴交点读出电源的电势为E=6V,其斜率等于电源的内阻,r=
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