某同学用刻度尺测金属丝的长度l,用螺旋测微器测金属丝的直径d,

某同学用刻度尺测金属丝的长度l,用螺旋测微器测金属丝的直径d,其示数分别如图1和图2所示,则金属丝长度l=________cm,金属丝直径d=         mm。他还用多用电表按正确的操作程序测出了它的阻值,测量时选用“×1”欧姆挡,示数如图3所示,则金属丝的电阻R=_________Ω

1

2                                                   3


答案

40.25±0.01  …………………………………………………………………………(2分)

     0.227±0.002 …………………………………………………………………………(2分)

     9 ………………………………………………………………………………………(2分)

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