我们知道导体达到静电平衡后,电荷是分布在它的表面的,下面我们通过一个带电金属球的实例计算,说明把金属导体带电看成“面分布”的理由. We know that after the conductor reaches the electrostatic equilibrium, the charge is distributed on its surface. In the following, we calculate through an example of a charged metal ball to illustrate the reason why the metal conductor is charged as a “surface distribution”.