We have long been inseparable from electricity in our daily lives. Junior high school physics has told us that electricity is actually generated by the movement of electrons. So many people will definitely ask, why are there so many electrons in generators unable to be used up?
In fact, there is no need for us to think of electricity too mysteriously. It is just invisible and intangible. In fact, it has many similarities with water flow.
For example, in a closed water system, under the action of a water pump, the water is circulating, and in this process, the water molecules do not decrease at all. Because these water molecules do not come from water pumps, but exist in the waterway.
. The generator is actually equivalent to a water pump. It does not generate any electrons themselves. All electrons come from the wires. The generator just gives the electron a driving force, just like a water pump driving water molecules.
In more professional terms, the engine only provides one potential energy. Under the action of the potential energy, electrons will flow in the wire, thereby generating a current.
electrons will not decrease during the flow process, just like water molecules will not decrease. In DC circuit , electrons flow back and forth between the positive and negative electrodes, so no matter what, electrons are used up.
explore more deeply. In fact, the basic principle of a generator is the Faraday law of electromagnetic induction. We have learned it in physics class, but many people have long forgotten it.
Simply put, this is what it means. The generator is a combination structure of a magnetic field plus a conductor. The conductor moves in the magnetic field through external forces, cutting the magnetic inductive line , thereby generating electric kinetic energy. In essence, electrons are affected by the Lorentz force .
Finally, it is said that the current propagation speed is very fast and reaches the speed of light. But from a microscopic perspective, the movement speed of electrons is not that fast, and it is even very slow, and can only move a few centimeters per second, which is far from the speed of light.
So why can the current speed reach the speed of light?
Simply put, because the speed of the electric field is the speed of light, an electric field is established in the conductor at the moment of turning on the power supply, and all electrons begin to move under the action of the electric field.
Therefore, the speed of the current is essentially the speed of the electric field, not the speed of the electron moving.
Also use water flow to give an image example. Suppose there is a water pipe that is one thousand meters long. When you turn on the faucet at home, tap water will flow out. The tap water flowing out is not water a thousand meters away, but water near the faucet. The moment you turn on the faucet, all the water in the water pipe will move.
The speed of current is actually the speed of water pressure transfer, not the speed of water flow.
