We know that the basic unit of all matter is the atom, that is, it is composed of atoms, which in turn are composed of a nucleus and extra-nuclear electrons.
In this sense, electrons are present in all matter.But some substances are not capable of transmitting electric current, such as wood and plastic. Why is this?
Because matter is divided into conducting and non-conducting substances, that is, conductors and non-conductors.
Conductors are substances that have a low electrical resistivity and conduct electricity easily, and metals are the most common conductors. This is because the valence electrons in the outermost layers of metal atoms can easily break free from the atomic nucleus and become free electrons, and the concentration of these free electrons inside the metal is very large, so the conductivity is large.
The concentration of free electrons in metals and graphite reaches 10^22/cm?, so the resistivity is small, only about 10^18?m, and the conductivity is large.
Therefore, the generator and its power transmission conductor is not any substance can do, only the metal graphite can take this role.
Metal can move freely in the charged particles, called carriers, under the action of the external electric field, do directional movement, it will form a significant current.
Human beings have an understanding of ? electricity? s exploration. Electricity? is a very amazing thing, human beings to? electricity? s earliest realization was lightning.Ancient people were curious about lightning, and Chinese mythology has the legend of the Thunder God and the Electric Mother, full of reverence for this mysterious and tremendous power.
Ancient Greece and Ancient India and Arabia all had some research on this phenomenon, but all stayed at the cultural level. It wasn't until 1600 that William, the royal physician to Queen Elizabeth of England? Gilbert, did not put ? electricity? into the orbit of scientific research, and began to carry out some preliminary explorations of electromagnetism. He left behind his book On Magnets, which is considered to be the earliest scientific work to deal with electromagnetic theory.
In 1752, Benjamin? Franklin then proved that lightning is a phenomenon of electricity through kite-induced lightning, and later he discovered the law of conservation of electric charge. The study of electromagnetism was formally put on a scientific track.
Then there were many scientists discovered some properties of electricity, such as Coulomb's law, voltaic pile (volt), ampere and so on, these discoveries are named after scientists, has been used to this day.
In 1831, British physicist and chemist Michael? Faraday discovered the interconnection and transformation relationship between magnetism and electricity, and that changes in magnetic fields generate electric fields, discovering electromagnetic induction and induced currents.
This great scientist, who only attended elementary school and became a self-taught scientist through hard work, made a key breakthrough in electric field theory, thus changing the world and bringing mankind from darkness to light.
In 1865, the great scientist James? Maxwell, on the basis of inheriting Faraday's research, integrated electromagnetism and proposed Maxwell's system of equations, deriving the electromagnetic wave equation, whose calculated electromagnetic wave speed is equal to the speed of light, thus boldly predicting that light waves are electromagnetic waves.
Maxwell will be electricity, magnetism and optics united into a theory, from the photoelectricity of the research flourished, a large number of scientists discovered and invented, so that the whole world civilization towards a complete change.
Now let's talk about how electricity is emitted.Electromagnetic theory tells us that an electric current is produced when a conductor cuts against a line of magnetic force.
There are two conditions for the phenomenon of electromagnetic induction to occur: 1. a closed circuit, and 2. a change in the magnetic flux through the closed circuit.
These two are indispensable.
Faraday based on their own discovery of this amount of theory, invented the first human disc generator
Cutting two ways, one is the conductor closed, the conductor does not move, through the conductor ring of magnetic flux changes; the other is the magnetic field is unchanged, the conductor relative to the magnetic field movement. Both variations are used to get current by cutting the magnetic lines of force.
The generator operates according to the second way to get current. The generator consists of a stator and a rotor combined, a magnetic field is generated in the stator and the rotor rotates in the stator, making a motion cutting the magnetic lines of force, which creates an induced potential difference, which is led through the terminals and connected to the circuit, and a current is generated.
The potential difference is the pressure difference of the current, which is commonly known as voltage.
As a result of the potential difference between the positive and negative poles in a closed circuit, charge flows up at both ends.
Definition of Potential Difference (Voltage Difference):
The charge q moves from point A to point B in an electric field, and the ratio of the work done by the force of the electric field, WAB, to the charge, q, is called the potential difference between the two points of AB (the difference in potential between the two points of AB is also known as the potential difference), and is expressed in terms of UAB, which is given by the formula:
WAB = WAB/q
With the equation. WAB is the work done by the electric field force and q is the charge.
If the closed circuit is a coil of N turns the electric potential energy can be expressed by the formula:? =N*? /?t (?t?0)
In the formula, ? is the induced electromotive force generated, in V (volts, referred to as volts); N is the number of turns of the coil, ? is the change in magnetic flux in Wb (Weber) , and ?t is the time taken for the change to occur in s (seconds).
Please note that the two necessary conditions for generating electricity are ? A closed circuit? and ? A change in magnetic flux?These are the two most important key points.
Let's start with ? Closed circuit?Without this ? closed? there would be no electricity generated. That is, the electricity from the generator passing through the conductor must have a loop back into the generator, forming a closed loop, for the current to be able to form.
The conductor mentioned here is the metal wire mentioned earlier, and power generation is driven by electromagnetic induction to the flow of free electrons in the wire. Generator power is generated by an electric field emitted by a generator, which passes through the wire and allows the current to flow in a loop.
That's why we need to butt the fire and zero wires when we connect appliances; the fire wire is the electricity that flows through, and the zero wire is the loop back to the generator.
This is true even with batteries.
The flow of electrons doesn't really go far, but rather one electron after another in a ? relay race? that passes the current down one carrier at a time and then back through the loop to the generator.
So the generator generates electricity not by flowing electrons out of itself, there is no question of the flow being complete or not.
So what about changes in magnetic flux?Magnetic flux is a physical quantity that represents the distribution of a magnetic field.
Located in the magnetic induction strength of B in a uniform magnetic field, there is an area of S and perpendicular to the direction of the magnetic field of the plane, the magnetic induction strength of B and the product of the area of S, called the magnetic flux through this plane, referred to as magnetic flux (Magnetic Flux). Scalar, symbol.
= BS, which applies if B is perpendicular to the SMagnetic Flux Calculation Formula in the case where the magnetic field is not perpendicular to the plane
Perpendicular to the plane. As shown in the figure, when there is an angle between S and the vertical plane of B? When ? =B?S?cos?
In layman's terms, a wire with a closed circuit cutting a line of magnetic force undergoes a change in magnetic flux, and the change in flux produces a potential difference.
This is because if a part of the conductor in the closed circuit moves in the magnetic field by cutting the line of magnetic induction, the electrons in the conductor are subjected to the Lorentz force, which is a non-static force that causes a potential difference, thus generating an electric current.
The potential difference creates an electric field that reaches the ends of the conductor at the speed of light, driving the electrons to move in a directional direction and delivering an electric current.
So what's the deal with current transport at the speed of light?Once formed, the potential energy of the generator forming a closed circuit reaches the ends of the conductor at the speed of light in the form of an electric field, initiating the flow of electric current at the speed of light, and thus exhibiting a current speed comparable to the speed of light.
We can also imagine a tap, and as soon as the tap is opened, water flows out. But this water is not fresh from the tap, it is pooling in the pipes.
The same is true of conductors; once an electromagnetic field is present, the electrons that have accumulated in the wire begin to transmit current. Of course the EM field transmits at the speed of light, whereas tap water is just the speed of mechanical forces, and the water pressure transmits at the speed of sound in water, which is about 1500 meters per second.
Note that it says the electric field reaches the user at the speed of light, not the electrons from the generator directly? brush? s reach the user at the speed of light, nor are the electrons one by one? relay race? reach the user so quickly.
Once the electric field is activated at the speed of light, the electrons in the range of the electric field catch wind of it, and the transfer of current begins, and within the speed of light, all the electrons are activated at the same time, and it feels as if the transfer of electrons has reached the speed of light.
In fact, the directional flow of electrons is very slow, only 0.1 millimeters per second, slower than the speed of a turtle.
But in an electric field, it is instantaneously initiated at a range of light speeds.
Theoretically, we can understand that during the transmission of an electromagnetic wave, the electrons don't really move, but rather form a matrix throughout the circuit which has a definite direction due to the potential difference, i.e., directional movement. This movement is actually a vibration in the original position in which a current is transmitted in one direction.
What is an electric field?The electric field is a special substance, which is not composed of molecules or atoms, but exists objectively in the space around the electric charge, i.e., the changing magnetic field, and is a special substance, which has the properties of energy and force.
The electric field does work on the charge placed in it and this force is called electric field force.
The formula for calculating the electric field force is F=qE
Where F is the force of the electric field on the point charge, q is the charge of the point charge, and E is the field strength.
The propagation speed of an electric field is about the speed of light in a vacuum, and the propagation speed of electricity actually refers to the speed of the electric field, not the speed of the electrons, which is also referred to by some as the electric signal.
Electricity? Propagation process: the circuit is not connected before the metal wire, although there are free electrons everywhere, but due to the wire without electric field, free electrons will only do irregular thermal movement without directional movement, the wire will not be current, the entire wire is in electrostatic equilibrium.When the circuit is turned on, the electric field will be immediately at the speed of light to transfer the field source change information, so that the circuit everywhere in the wire quickly established electric field, electric field immediately push the speed of light to cage the range of free electrons to do directional drift movement, the formation of current.
Thus, a current from a power source can be energized in any direction by flipping a switch at almost the same moment.
And the electric field is created because there is a potential difference, or voltage, at the ends of the conductor, and the power supply is designed to maintain the voltage at the ends of the conductor so that there is a constant electric field force in the circuit to ensure that the current continues.
Either the generator or the battery form of power supply has this property.
In real life, not all electricity is delivered directly from the generator to the end-user, depending on the user needs and in order to reduce line losses, but also need to go through the process of transformer, boosting, reducing and so on.
Conclusion: the current is not a generator inside the electron outflow, but the electric field force to make the conductor free electrons directed to move, the electrons in which only play ? mover? s role; and this ? Carrier? Just through the vibration back and forth to transfer energy, for closed-loop movement, and no substantial movement; as long as the electric field exists, ? The electrons? will never finish flowing.
Current reaches the speed of light, not how fast the electrons are moving, but how fast the electric field is transferring the energy to reach the speed of light, and the electric field force drives the current to reach the speed of light.
Thanks for reading, and welcome to the discussion.
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