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初中物理第二册“电流的效应”一节安排了电流的化学效应和磁效应两个演示实验。我们按照课本图7-15,采用3节甲种电池进行实验,测得电路中电流强度大于3安培,这样强的电流是不太适合化学电池长时间放电的。对于图7-16这一演示实验,由于缠在铁钉上绝缘导线的直流电阻接近于零,外电路趋近于短路,电流大得无法用学生用安培表测出,我们将原实验作如下修改。实验所用器材是:3节甲种电池组成的串联电池组,2.4V小电灯泡
The second chapter of the junior high school physics “current effect” section arranges two demonstration experiments of the chemical effects and magnetic effects of currents. According to the textbooks in Figure 7-15, three sections of a battery are used for experiments. The measured current intensity in the circuit is greater than 3 amps. This strong current is not suitable for long-term discharge of chemical batteries. For the demonstration experiment of Fig. 7-16, since the DC resistance of the insulated wire wrapped around the nail is close to zero, the external circuit approaches a short circuit and the current is too high to be measured by the student using an ampere meter. We will make the original experiment as follows modify. The equipment used in the experiment was a series battery pack composed of 3 cells of one grade, a small bulb of 2.4V.