一、暴露问题在一次批改学生一题为2012年天津高考理综第11题的作业时,发现学生对物理量的平均值理解不深,应用中常常不明其理以至张冠李戴.现将试题和学生甲、乙的错误解法呈现如下.例1(2012年天津高考理综第11题)如图1所示,一对光滑的平行金属导轨固定在同一水平面内,导轨间距l=0.5 m,左端接有阻值R=0.3Ω的电阻,一质量m=0.1 kg,电阻r=0.1Ω的金 First, the issue of exposure In a correction of a student for the 2012 Tianjin University entrance exam comprehensive title of the 11th homework, students found that the average physical value of the understanding is not deep, the application is often unknown and Zhang Guan Li Dai now test questions and student A , B’s error solution is presented as follows: Example 1 (2012 Tianjin Entrance Examination Carcass 11) As shown in Figure 1, a pair of smooth parallel metal rails fixed in the same horizontal plane, the guide rail spacing l = 0.5 m, the left end of the Resistance R = 0.3Ω resistance, a mass m = 0.1 kg, resistance r = 0.1Ω gold