Motion charges can cause fluctuations. The fluctuation mechanism is: when the motion charge e is moving, it is bound to be hindered by its adjacent e, which is characterized by the motion charge driving its adjacent 1 upward movement, that is, adjacent to the movement charge e together upward movement, when adjacent to 1 upward movement, is bound to be adjacent to its own 1 of the obstruction, manifested as adjacent to 1 to drive its own That is, adjacent to 2 along with the adjacent 1 together upward movement ... In this way, the forward propagation, the formation of fluctuations.
Obviously, the rate of transmission of this fluctuation in real air is the speed of light. What effect does the fluctuation generated by the motion charge have on the small magnetic needle? Take the linear current as an example to analyze it. The small magnetic needle n is on the right side of the linear current I, and when the small magnetic needle n is reduced to a annular current ABCD, although points A, B, C and D are all within the fluctuation range of the linear current I, the energy size of the adjacent motion at points A, B, C and D varies. Apparently, ea>ec,eb=ed. As a result, the fluctuation of the linear current I has a clockwise torque on the annular current ABCD of the small magnetic needle n. The moment acts on the electrons that rotate around the nucleus, making it rotate clockwise, and its macroscopic expression is the North Pole vertical paper outward of the small magnetic needle n.