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由于电位具有相对性,导致了一个新问题——电位参考零点的选择问题。通常情况,电位的参考点选择有一定任意性,但又不是完全任意的,主要看问题的性质和研究的方便。参考点选择不当,会使计算麻烦,导致错误的结论。对于成人学员来说怎样选择电位参考零点困难是很大的,下面针对三种具体情况,谈谈选择方法。(一)、有限带电体。其电位分布在有限空间里,通常以无限远为其电位参考零点,运算方便,电位的数学表达式最简单。如图(1)所示,在点电荷激发的电场里,求距点电荷为r_0点的电位时,就是求该点和电位零点的电位差。如果我们把参考点选择在点电荷上得到U=,这里的被积函数并不简
Due to the relativity of potentials, a new problem is caused, which is the choice of potential reference zero. Usually, the potential of the reference point to choose a certain arbitrary, but not completely arbitrary, mainly to see the nature of the problem and the convenience of the study. Improper selection of reference points can make the calculation cumbersome and lead to erroneous conclusions. It is very difficult for the adult learner to choose the potential reference zero. The following three specific situations are discussed about the selection method. (A), limited charged body. Its potential distribution in a limited space, usually at infinity for its potential reference zero, easy to operate, the potential of the mathematical expression of the simplest. As shown in figure (1), in the electric field excited by the point charge, when the electric potential of the point r_0 is obtained, the potential difference between the point and the potential zero point is obtained. If we choose U = on the point charge, the integrand is not simple