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零电位的选择,原则上是可以任意的,但对研究孤立电荷的电位,取“无限远”为零电位,较为有利,会带来公式的简化。比如,研究点电荷Q附近P点的电位大小,我们通常用Q电荷的电场力对试探电荷q_0(取单位正电荷)作功的大小来描述:选“无限远”为零电位,即r_b→∞,则电位公式便简化成: 可见,这种选择在理论上研究问题是十分方便的。但是,这仅是一种理想模型,很难用实验证明。因为人类栖息在地球上,而地球是一个带电的“球壳形电容器”,其正
The selection of zero potential can in principle be arbitrary, but it is advantageous to study the potential of isolated charges and take “infinity” zero potential, which will bring about the simplification of the formula. For example, to study the potential of point P near point Q, we usually use the electric field force of the Q charge to describe the amount of work done on the test charge q_0 (by taking the unit positive charge): select “infinity” zero potential, that is, r_b→ ∞, then the potential formula is simplified: Visible, this choice is theoretically very convenient to study the problem. However, this is only an ideal model and it is difficult to prove it experimentally. Because humans inhabit Earth, the Earth is a charged “ball and shell capacitor”.