What is Induced EMF Microscopic Explanation 10

Induce electromotive force.

Microscopically it is the change in the magnetic field that produces an electric field, which then drives the flow of electrons in the conductor to form an electric current. Macroscopically, it is the magnetic flux.

The change led to the emergence of electromotive force.

Due to the change in the magnetic field with time, an electric field is created in space. However, since the integral of this electric field along most closed curves is not 0, it is impossible to find a potential field corresponding to this electric field. Fortunately, as long as b does not change with time, the electric field is integrated along a fixed curve.

It's fixed. Therefore, it is also possible to use potential to equivalentize the action of the electric field on the charge.

From the perspective of energy, in the kinetic electromotive force, the force and the direction of motion are perpendicular, so the magnetic field does not do work on the electrons, and the energy of the electrons is the reason for the movement of the conductor. In the induced electromotive force, the charge is acted upon by an electric field, which is an electromagnetic field.

Give energy to the charge.

The changing magnetic field generates an electric field in the surrounding space, and when the conductor is in this electric field, the free electrons in the conductor move directionally under the action of the electric field force to produce an electric current, that is, an induced current; If the loop is not closed, the directional movement of free electrons in the conductor causes positive and negative charges to accumulate at both ends of the disconnect, resulting in a potential difference – induced electromotive force.

Induced electromotive force: The electromotive force produced in the phenomenon of electromagnetic induction.

There is an induced electromotive force to form an induced current.

Induce electromotive force. YesElectromagnetic induction phenomenonSince there is an induced current in the closed circuit, there must also be an electromotive force in this circuit, and the electromotive force generated in the electromagnetic induction phenomenon is called induced electromotive force.

1 The magnetic flux that passes through the circuit regardless of whether the circuit is closed or not.

When there is a change, an induced electromotive force is generated in the circuit, and the generation of induced electromotive force is the essence of the electromagnetic induction phenomenon.

2. Whether the magnetic flux changes is the fundamental reason for the electromagnetic induction, if the magnetic flux changes, the circuit will generate induced electromotive force, and if the circuit is closed, there will be induced current in the circuit.

3. The generation of induced current is just a phenomenon, which indicates that electrical energy is being delivered in the circuit; The generation of induced electromotive force is the essence of the electromagnetic induction phenomenon, which indicates that the circuit has the ability to output electrical energy at any time.

4When the magnetic flux changes the same, the greater the time t used, that is, the slower the magnetic flux change, the smaller the induced electromotive force e; Conversely, the smaller t is, the faster the magnetic flux changes, and the greater the induced electromotive force e.

5. When the change time t is the same, the greater the change, the faster the change of magnetic flux, and the greater the induced electromotive force e;Conversely, the smaller the change, the slower the change in magnetic flux and the smaller the induced electromotive force e.

Introduction to the generation of induced electromotive force

The movement of the conductor cutting magnetic inductance line generates an induced electromotive force, and the metal conductor rod AB with length L moves in a uniform linear motion with a vertical and uniform magnetic field B at velocity V.

Free electrons inside the rod.

The rod moves in a magnetic field, and according to the left-handed rule, it can be seen that there are free electrons.

will be subject to the Lorentz force.

Directional movement in the AB direction, (After the free electron begins to move directionally, the Lorentz force is perpendicular to the direction of the resultant velocity, and the magnetic induction intensity.

The change creates an induced electromotive force.

Study a plane below a magnet. When the magnet moves downward, the intensity of the magnetic induction at each position on this plane changes, according to the "Electromagnetic Field" Chapter 19.

and electromagnetic waves "will learn the knowledge of the change of the vertical dry magnetic field week."

The induced electromotive force produced by the change in magnetic induction intensity is proportional to the rate of change of the magnetic flux: te.

An induced current is generated.

Condition: As long as the magnetic flux passes through a closed circuit.

When there is a change, i.e. ≠0, there is an induced current in the closed circuit.

Induced electromotive force is generated.

Conditions: Regardless of whether the circuit is closed or not, as long as the magnetic flux of the closed circuit passing through changes, there is an induced electromotive force in the circuit, and the part of the conductor that generates the induced electromotive force is equivalent to the power supply. Electromagnetic induction phenomenon

The essence is to generate induced electromotive force, if the circuit is closed, there is an induced current, and if the circuit is not closed, there is only an induced electromotive force and no induced current.

The derivation process is as follows:

From Faraday's law of electromagnetic induction, it can be known:

e=δ tWhen the conductor rod cuts the magnetic inductance line, the tangent magnetic field line b does not change;

So δ =b*δs, s = l*s (l is the length of the conductor rod and s is the length of the loop in the magnetic field).

Because l does not change in the wild, then δs=l*δs δt* δt because v = δs δt, so δs=l*v* δt so δt=δs (l*v).

Substitute δ ,t with e=δ t

E=BLV

This is the formula for calculating induced electromotive force.

1) e=n*δ t (universal formula).

2) E=Blvsina (Cutting the Inductance Line Movement) The V and L in E=BLV cannot be parallel to the magnetic inductance line, but can not be perpendicular to the magnetic inductance line, where the angle A is the angle between V or L and the magnetic inductance line.

3) em=nbs (maximum induced electromotive force of alternator).

4) e=b(l2)2 (one end of the conductor is fixed to rotary cutting).

Electromotive Force Calculation Method:

The direction can be determined by Lenz's law. Lenz's law of high school physics states that the magnetic field of the induced current should hinder the change of the original magnetic flux.

For the kinetic electromotive force, students can also use the right-hand rule to judge the direction of the induced current, and also find out the direction of the induced electromotive force. It should be noted that Lenz's law is more widely used, and its core lies in the word "hindrance".

The direction of the induced electromotive force (or the direction of the induced current) is related to the direction of the high, wide and empty magnetic field and the direction of the conductor movement, and the relationship between them can be determined by the right-hand rule. Experiments show that in a uniform magnetic field, the magnitude of the induced electromotive force generated by the movement of the wire as a magnet line and the magnetic induction intensity b, the length of the wire l, the speed of the conductor motion v, and the angle between the direction of the conductor movement and the direction of the magnetic field.

The induced electromotive force is generated under the conditions of inductive reactance and changing current. For example, the transformer induces electromotive force by the primary inductive reactance and the initial lead laughing level of alternating current.

For example, the induced electromotive force of the ignition coil of the automobile hand shield is provided by the primary inductive reactance and the primary pulsating direct current, while the electromagnet also has inductive reactance, but the current does not change, so the electromagnet can only produce magnets by itself.

instead of generating an induced electromotive force that couples energy to a secondary similar to the next stage.

The principle of induced electromotive forceThe principle of induced electromotive force generation, if there is an electric current in the closed line, there must be the principle of electromotive force water flowing to a lower place. The current is caused by the electromotive force of the power supply. The electromotive force produced in the phenomenon of electromagnetic induction is called induced electromotive force.

The part that generates the induced electromotive force is used to cut the conductor of the locust potato with the force line movement, which is equivalent to the power supply.

The magnitude of the induced electromotive force and the magnetic flux passing through the closed circuit.

The speed of change is related, that is, the magnetic induction intensity of the coil cutting the magnetic field lines.

The length of the conductor, the cutting speed, and the angle between the coil and the direction of the magnetic field lines are related.

Induced electromotive force explains the electromotive force produced in the phenomenon of electromagnetic induction. It is usually represented by the symbol e. When the magnetic flux through an unclosed coil changes, there is no induced current in the coil, but the induced electromotive force remains.

When a conductor cuts the magnetic inductance line at a uniform speed in a uniform magnetic field, regardless of whether the circuit is closed or not, the magnitude of the induced electromotive force is only proportional to the magnetic induction intensity b, the length of the conductor l, the cutting speed v and the sine value of the angle between v and b directions, that is, e blvsin.

Word decomposition Explanation of induction Physics noun . The electric charge, magnetism, or electromotive force generated by the proximity but not contact of another similarly excited object or the change in magnetic flux caused by the external influence of an object such as an electrical conductor, a magnetizable body, or an electrical circuit Explanation of electromotive force The work done by a unit of positive charge moving along the circuit for one week is called the electromotive force of the power supply. When the power supply does not output current, the electromotive force of the power supply is equal to the potential difference between the poles.

The unit is volts.

Electromotive force is the tendency of electrons to move, which can overcome the resistance of the conductor resistance to the electric current, so that the charge flows in a closed conductor loop. This action is due to the corresponding physical or chemical effect, and is usually accompanied by the conversion of energy, because the energy consumed when the current starts and flows in the conductor, and this energy must be compensated by the energy that generates the electromotive force. If the electromotive force occurs only in a part of the conductor circuit, the excitation domain of that partition is called the power region.

There is also resistance in the power supply area, which is called the internal resistance of the power supply. The energy consumed in the conductor circuit outside the power supply area is directly related to the electromagnetic field in the conductor, but the energy of the electromagnetic field still comes from the power supply.

In the phenomenon of electromagnetic induction, if there is an induced current in the circuit closed, then there must also be an electromotive force in the circuit, and the electromotive force generated in the electromagnetic induction phenomenon is called induced electromotive force.