# 交变电场速度测量的物理原理Physical Principles of Measuring the Speed of Alternating Electric Field

Abstract: AC electromotive force generates alternating potential differences and longitudinal electric fields in a circuit. The speed of alternating electric field within the metal wire is not constant, which is related to the circuit parameters. In most cases, the speed of alternating electric field is lower than the speed of light. However, under certain circuit parameters, the speed of alternating electric field can be 20 times more than the speed of light. This paper analyzes the time delay of the alternating electric field in RL circuits. The formula of the speed of alternating electric field in a wire is deduced.

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