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下面就通过一道2012年高考北京卷实验题中的第(2)和第(4)小问来看看高考中需要我们掌握的列表法和作图法.2012年北京卷在“测定金属的电阻率”实验中,所用测量仪器均已校准.待测金属丝接入电路部分的长度约为50cm.(2)用伏安法测金属丝的电阻Rx.实验所用器材:电池组(电动势为3V,内阻约1Ω)、电流表(内阻约0.1Ω)、电压表(内阻约3kΩ)、滑动变阻器R(0~20Ω,额定电流2A)、开关、导线
The following on a college entrance examination in Beijing in 2012 by the test questions (2) and (4) a small question to take a look at the college entrance examination need us to master the list method and mapping method .2012 Beijing volume in the “determination of metal Resistivity ”test, the measuring instruments used have been calibrated. The length of the wire to be tested is about 50 cm. (2) The resistance of the wire measured by voltammetry Rx. Equipment used in the experiment: battery (electromotive force 3V, internal resistance about 1Ω), ammeter (internal resistance about 0.1Ω), voltmeter (internal resistance about 3kΩ), sliding rheostat R (0 ~ 20Ω, rated current 2A), switch, wire