一、在存在多个变量时,要确定“分界点”例1 金属的电阻随温度的升高而增大,小灯泡发光时,灯丝电阻比不发光大得多,在课外兴趣小组活动时,某校两位同学用实验研究小灯泡的电功率跟两端所加电压的关系,所接的电路图如图1所示(两人所用仪器的规格相同)。 First, in the presence of multiple variables, to determine the “demarcation point” Example 1 Metal resistance increases with the temperature increases, a small bulb light, the filament resistance is not much greater than the non-luminescence, in extracurricular interest group activities At that time, two students from a certain school used the experiment to study the relationship between the electric power of a small light bulb and the applied voltage at both ends. The circuit diagram connected is shown in Figure 1 (the specifications of the instruments used by the two are the same).