What is the relationship between electricity and magnetism?

The unit on electricity and magnetism covers three parts.

1. The magnetic effect of electric current.

Trial: Oersted's test.

Connect a circuit, put some small magnetic needles next to it, close the circuit, and the magnetic needles deflect in different directions.

Important: Judgment of the poles of the solenoid (electromagnet) - the right-hand rule (the finger of the right hand is in line with the direction of the current, hold the solenoid, and the direction of the thumb is the North Pole).

Application: electromagnetic crane, magnetic punching machine, electromagnetic concentrator, etc.

2. Electromagnetic induction.

Test: Faraday test or electromagnetic induction test.

A part of the conductor in the closed circuit cuts the magnetic inductance line in the magnetic field and generates an induced current (in order to make the test phenomenon obvious, a coil is used instead of a straight wire, and a sensitive galvanometer is used to indicate the induced current).

Influencing factors of induced current: direction The direction of the magnetic field, the direction of the cutting magnetic inductance line.

The size of the number of turns of the coil, the strength of the magnetic field.

Understand: A method for determining the direction of an induced current – Ampere's rule.

Applications: Generators, transformers, dynamic microphones.

3. The effect of magnetic field on electric current.

Test: Connect a circuit with a power supply, coil, etc., and put the coil into the magnetic field after it is turned on, and find that the current in the coil is affected by the magnetic field and drives the coil to move.

Understand: The left-handed rule for determining the direction of movement of a coil.

Application: Electric motor.

This summary is still written by yourself, the summary is a very important learning process, no less important than you take the class again, and the class cannot replace the role of the summary.

If it's certain questions, there's no harm in asking someone else to help you solve them.

The unit of electromagnetism has a series of formulas, all of which are intrinsically related to each other. It is much more useful to derive one side by yourself than to look at other people's summaries.

Oops——— what's the matter with you, the teacher won't let you go on, you still go on.

I think it's better to summarize it yourself, so that it will be good for memorizing this part. There are still many difficulties in the future, which you need to solve by yourself.

1. Interaction between magnetic poles.

2. Magnetic field. 3. The related concepts of magnetic inductance lines.

4. Oersted experiment.

5. Ampere's rule.

6. Application of electromagnets.

7. The force of the energized conductor in the magnetic field.

8. Electromagnetic induction.

In the narrow sense, the material is the objective world that we can see. 2.Energy states, some matter also exist in forms that we cannot see, and although we cannot see them, they are "as real as the chairs we sit on" (Einstein).

These substances play an extremely important role in our lives, for example, the signal received by our mobile phones is one of the most commonly used by us. 3.Condensed matter, also known as the particle state, is the third state of matter proposed by Einstein, but it has been discovered for a long time, and this is the least common for us, but it does exist, such as the superconducting state.

Electricity and magnetism are essentially the same substance, it can be said that there is no electricity, but there is magnetism, when the magnetic field changes for some reason, whether there is a medium or not, it will produce a substance to propagate the magnetic field, this substance is the electric field, when there is a medium, the magnetic field passes through the substance in the form of magnetic field lines, and the electric field acts on the substance in the form of voltage, when the substance can produce a current path, that is, when the substance is a conductor, then it will produce a current under the action of voltage.

What is the relationship between electricity and magnetism? To put it simply, the acoustic signal is converted into an electromagnetic signal, and then the electromagnetic signal is converted into an acoustic signal. Specifically, communication is through the conversion of sound energy and electrical energy, and the use of "electricity".

A magnetic field is generated around an electric current, see Biosavall's law, and see also the Ampere molecular circulation hypothesis...

The magnetic field does work on the moving electrons, causing the electrons to move in one direction...

A field is a substance, and there will be interactions between matter...

This is the experiment first discovered and then there is a theory and application, not everything can be **, that guy took decades to discover it is strong.

This is a discovery of Phaladis and there is currently no new explanation.

First of all, it is difficult to have an absolute vacuum.

Even if there is an absolute vacuum, it will still have a force. The role of other dimensions.

Magnetic Effect of Current: Discovered by Oersted, the dismantling refers to the presence of a magnetic field around an energized conductor. The main point is that the electricity is applied first, and then there is a magnetic field;

Electromagnetism: refers to the magnetic effect of electric current. i.e. the content of the surface above.

Energized conductors are subjected to force in a magnetic field: the principle of an electric motor. The reason is that there is a magnetic field around the energized conductor, which is equivalent to a magnet, and this magnet is placed in the magnetic field, because there is an interaction surface between the poles to experience the force.

The presence of a magnetic field around an energized conductor is the magnetic effect of the electric current, i.e., electromagnetism. God envy.

So, these four, three of them: magnetic effect, electro-generated magnetism, and the presence of a magnetic field around an energized conductor, are the same.

A moving charge can produce a magnetic field, in fact, a time-varying electric field produces a magnetic field, and a time-varying magnetic field can produce an electric field.

From electrodynamics, it can be deduced that the magnetic field is actually a relativistic effect of the electric field, which is about the same order of magnitude as 1 (v -c) of the electric field, but because most of the macroscopic objects are electrically neutral, and most of the electric forces in between them are canceled, the magnetic field force will manifest. In general, when discussing the interaction between microscopic particles, the main discussion is about electricity, and the magnetic field force is negligible (except for some specific occasions that are used).

The concept of field was first introduced artificially to solve the problem of the distance of force applied in electromagnetic interactions, for example two discrete charges can produce electric action, and in order to explain this force, we believe that there is an electric field around these two charges, and electricity interacts through an electric field. Later, the discovery of electromagnetic waves made us realize that fields are not just our "imaginary" concepts, electromagnetic waves are moving electromagnetic fields, which have energy and momentum! This gives the field its materiality.

According to my understanding, the nature of the field can be seen in the nature of light (light is also an electromagnetic wave), that is, it is not measurable at rest and can be used as a medium of electromagnetic force, and the field of motion has momentum and mass.

The essence of the field is f(x,y,z,t), that is, a numerical value in spatial and temporal coordinates, which distinguishes it from another way of existence of matter.

Macroscopically, the proton is regarded as the smallest charged unit, and the amount of charge e, the rotation has no effect on the space around it.

The electric field of motion can produce a magnetic field, which is the view of Maxwell's classical electromagnetism, and in Einstein's theory of relativity, the magnetic field is the relativistic effect of the electric field.

(1) It can be said that the motion of an electric field can produce a magnetic field. The magnetic field is actually a correction of the external action of the electric field excited by the moving charge, so in fact, the essence of the electromagnetic field is the same, and the electromagnetic field is not distinguished in the theory of relativity.

2) Electric and magnetic fields will be excited in space.

The field is a substance, but it is not the same as the material properties that we have always had, it has momentum and energy (electromagnetic energy is stored in the field), but it does not occupy space, but is diffused in space.