The speed of electricity in red copper cable is more than 1 10000 kilometers per second, platinum is more than 160000 kilometers per second, and gold is more than 200000 kilometers per second. All electronic conductors are plastic. Only in a vacuum system can we approach the speed of light, or it can be said that it is the speed of light. Because light has zero mass and electrons have mass, it is unlikely to be faster than light or as fast as light, but they are not far apart and can be ignored. None of the known speeds can reach or exceed the speed of light, but they are all close to it.

Cathode rays are composed of negatively charged particles, that is, cathode rays are a stream of electrons. Let this electron flow vertically into the uniform electric field and uniform magnetic field perpendicular to each other, and change the magnetic field intensity or magnetic induction intensity, so that the orientation of the fitness movement of this negatively charged particle will not change. At this time, the electrostatic force eE is just equivalent to the magnetic field force eBv, that is, eE=eBv, then the electronic fitness movement speed v=E/B can be obtained. 1894, Thomson measured the speed of cathode ray as11500, which is about 2× 105 m/s, assuming that the number of free electrons in the enterprise volume of copper transmission line is n, the electron term moves to v, the electric quantity of each electron is e, and the cross-sectional area of transmission line is s,. According to v=I/neS of I=Q/t, the data brought in can get v = 7.4× 10-5m/s, that is, 0.74 mm/s. 。

According to the above data, the velocity of free electrons in the conductor (about 10-4m/s) is about 109 times smaller than the average velocity of free electrons' thermal motion (about 105m/s). This shows that the current is generated by the low-speed motion of all free electrons in the conductor. Why? Although the velocity of free electrons in metal conductor is not large, it accumulates and exceeds a larger thermal velocity of electrons.

Just like the speed of wave is not large, if the sound is converted into an analog signal and carried on high-frequency radio waves, its outward propagation speed is equivalent to the speed of light (c=3× 108 m/s). The transmission speed of current (equivalent to the propagation speed of electrostatic field) is very large (equivalent to the speed of light). Because of the conductivity of metal materials, electrons can move at will. Under the action of electromagnetic field, the free electrons in the conductor basically cause an additional fixed term velocity opposite to the direction of the electric field, and the average value of this velocity is called drift velocity. Generally speaking, the drift velocity of electrons in conductors made of other metal materials is also around 10-4m/s, while the average thermal velocity of free electrons in metal materials is in the order of 105 m/s, which shows that the fixed term drift velocity of free electrons under the action of electrostatic field is much lower than the average thermal velocity.