大家知道,静止电荷产生静电场,运动电荷不仅产生电场还要产生磁场。但运动和静止本身是相对的,是对某一参照系而言的。所以静止电荷引起的效应和运动电荷引起的效应之间的差别不是根本性的,或者讲电场和磁场密切相关,可以互相转化。它仅取决于特定参照系的使用。(我们通常讲的运动与静止是对于实验室参照系而言的)。在一个参照系看来是静止的电荷,它在这参照系中是静电场的源电荷,而在另一参照系看来此电荷在运动,那末在后一参 As we all know, static charge generates electrostatic field, which not only generates electric field, but also generates magnetic field. However, movement and quiescence are relative in themselves and refer to a frame of reference. So the difference between the effects caused by the quiescent charge and those caused by the kinetic charge is not fundamental, or the electric field and the magnetic field are closely related and can be transformed into each other. It only depends on the use of a particular frame of reference. (The exercises and rests that we usually talk about are for the laboratory frame of reference.) In one frame of reference it appears to be a stationary charge, which is the source charge of the electrostatic field in this frame of reference, whereas in the other frame of reference this charge is in motion, then in the latter frame