1.等效法例1 ab 是长为 L 的均匀带电细杆,P_1、P_2是位于 ab 所在直线上的两点,位置如图1所示,ab 上电荷产生的静电场在 P_1处的场强大小为 E_1,在 P_2处的场强大小为 E_2,则以下说法正确的是( ) 1. Equivalent Example 1 ab is a uniformly-charged rod of length L. P_1 and P_2 are two points located on the straight line of ab. The position is shown in Fig. 1. The electrostatic field generated by charge on ab is the field strength at P_1. The size is E_1, the magnitude of the field strength at P_2 is E_2, then the following statement is correct ()