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在初中、高中课本中都提到温度对电阻的影响,为此我们设计了两个有趣的实验。实验一用火柴“点”电灯用导线将额定电压2.5伏左右的小电灯、一段长7厘米左右的铅笔芯、电源按图1串联成电路,铅笔芯上两接点 A、B 间距离约取2厘米,此时小电灯应发光。逐步增加铅笔芯上两接点 A、B 间的距离,直至看不见小电灯发的光为止。
The effects of temperature on resistance are mentioned in the textbooks for junior and senior high schools. For this reason, we designed two interesting experiments. In experiment 1, a small lamp with a rated voltage of about 2.5 volts, a pencil with a length of about 7 centimeters, and a power supply are connected in series as shown in Figure 1 using a match, point, and electric wire. The distance between two contacts A and B on the pencil lead is about Take 2 centimeters, at which point the small lamp should glow. Gradually increase the distance between the two contact points A and B on the pencil lead until you cannot see the light from the small lamp.