What are the similarities and differences between magnetic field strength and magnetic induction str

Magnetic field strength and magnetic induction strength are both physical quantities that characterize the strength and direction of the magnetic field.

Magnetic induction intensity is a basic physical quantity, which is easier to understand, that is, the number of magnetic field lines that pass perpendicular to a unit area. The magnetic induction intensity can be measured directly by the instrument. Magnetic induction intensity is also known as magnetic flux density, or magnetic density for short.

It is often denoted by b. Its units are Weber square meters (wb m 2) or Tesla (t).

The magnetic field propagates through a medium (including a vacuum), and the magnetization of the medium also generates a magnetic field, which is superimposed on the source magnetic field to produce another magnetic field. In other words, the strength and direction of the magnetic field generated by a magnetic field source changes after passing through the medium.

In order to describe the characteristics of the magnetic field source, and to facilitate mathematical derivation, a medium-independent physical quantity h, h=b u0-m, where u0 is the vacuum permeability and m is the magnetization of the medium. This physical quantity is the strength of the magnetic field. The unit of magnetic field strength is a meter (a m).

5. Electromagnetic wave propagation is carried out by mutual excitation of electric field and magnetic field, therefore, as long as the electric field is shielded, the propagation is truncated, and there is no need for magnetic field shielding, right?

1. Similarities: e=f q b=f il are both physical quantities that describe the properties of field forces; Spatial curves can be used to describe their size and orientation. It's all vectors.

2. Differences: As long as the electric field is not zero, it will have a strong effect on the charge put into it; In the magnetic field, the current element must be perpendicular to the direction of the magnetic field or have a certain angle, and the current element placed in parallel is not subject to force.

The description of the electric field is with electric field lines, the electric field lines are not closed, whereas the magnetic inductance lines are closed.

The intensity of magnetic induction is directly proportional to the strength of the magnetic field.

The strength of the magnetic field is a representation of the number of turns of the coil, which reflects the strength of the source of the magnetic field. The strength of the magnetic induction indicates the effect of the magnetic field source in a specific environment. In the past, when I was studying general physics, I mentioned the two concepts of magnetic induction intensity b and magnetic field strength h.

Because I have been neglecting to think, I have not carefully thought about the similarities and differences between the two.

The textbook says that h is an artificially introduced definition, which has no physical meaning, and does not think too much, and accepts it in its entirety. As for the more basic argument about H and B, I only remembered this fact, and I didn't think why, I was ashamed, and I didn't think about why they were called that. Over the past year, I have gradually understood the stories in the solid, and now that I think back, I have clarified their meaning.

Introduction to magnetic fields

b** Force on charged particles. For a particle at a certain velocity, with the addition of a h-magnetic field, orbital measurements, and Newtonian mechanics, you can measure the force on the particle. You find that the force is proportional to the charge number q and velocity, and also proportional to h, but the force f is not directly equal to qvh, but is a factor different:

f=a*q*v h, a is only a pending factor, and has not been given physical meaning for the time being.

How permeability is introduced. In this way, h is the magnetic field applied by the electric current, and the force applied to the particle directly defines the magnetic field felt by a particle, which is called b, in order to make f= qv b true. That is, when an external H-field is applied, the particle motion feels a B-field, which defines the permeability miu = b h, and the "rate" means proportion.

Magnetic permeability, which is the ratio of a particle's motion (force) to external magnetism, describes the response of the former with the latter. If the permeability is large, then the applied magnetic field h is also large, so that the response of the particle to the force (e.g., deflection) is also greater.

If the permeability is zero (non-permeable), then the magnetic field will not make the particle have a mechanical reaction such as deflection, if the permeability is almost infinite, you only need to add a little bit of the external magnetic field h, and the particle will already be deflected.

Generally speaking, if the magnetic induction intensity in space is represented by b, and the magnetic field strength is represented by h, they have the following relationship: h=b u-p, of course, h, b, p are all vectors. where u is the magnetic induction constant of the magnetic medium in space, u0 in the air, and p is the magnetization in the magnetic medium.

Of course, in general, in air, p can be considered equal to 0 and simplified to h=b u0. The similarity is that they can both represent the magnetic field at a point in space.

Difference Between Magnetic Field Strength and Magnetic Induction Intensity:

1.The meaning is different: the magnetic induction intensity refers to the physical quantity that describes the strength and direction of the magnetic field, and the commonly used symbol b indicates the force of the positive electromagnetic charge in the magnetic field in the unit of reduced field strength, and the commonly used symbol h represents it.

2.The units are different: the universal unit of magnetic induction strength is Tesla, and the unit of magnetic field strength is ampere meters.

3.The application is different: the magnetic induction intensity is used in the qualitative description of the magnetic field, while the magnetic field strength is mostly used in the calculation of the magnetic field, which is linearly related to the current.

1. The essence is different: the strength of the magnetic field is first drawn from the point of view of magnetic charge, and the essence of magnetic phenomena is molecular current. Magnetic induction strength refers to the physical quantity that describes the strength and direction of a magnetic field.

2. Different properties: The magnetic field strength describes the physical quantity of the magnetic field properties. The strength of the magnetic field in physics is expressed by the intensity of magnetic induction, and the greater the intensity of magnetic induction, the stronger the magnetic induction. The smaller the magnetic induction intensity, the weaker the magnetic induction.

3. Different: The magnetic induction intensity is obtained by the magnetic effect of the electric current, and the magnetic field strength is defined by the motion of charged particles in the magnetic field. The magnetic induction strength is more basic than the magnetic field strength because the current itself is generated by the motion of charged particles, so the particle model is more basic than the current model.

Magnetic field strengthIt was the first in history to be introduced by the idea of magnetic charge. Analogous to Coulomb's law of electric charge.

It is believed that there are two kinds of magnetic charges, positive and negative, in nature, and Coulomb's law of magnetic charge is proposed. The force exerted on a unit positive electromagnetic charge in a magnetic field is known as the magnetic field strength (symbol h).

Later amps. The molecular current hypothesis is proposed, which holds that there is no magnetic charge and that the essence of magnetic phenomena is molecular current. Since then, the strength of the magnetic field has mostly been magnetic induction.

The symbol is b). However, in the magnetization or slag spring problem of magnetic media, the magnetic field strength still plays an important role as an auxiliary quantity of derivation.

Magnetic Induction Intensity:It refers to the physical quantity that describes the strength and direction of the magnetic field, which is a vector quantity, commonly represented by the symbol b, and the international common unit is Tesla.

The symbol is t). Magnetic induction intensity is also known as magnetic flux density.

or magnetic flux density. In physics, the strength of a magnetic field is expressed in terms of the intensity of magnetic induction, and the greater the intensity of magnetic induction, the stronger the magnetic induction. The smaller the magnetic induction intensity, the weaker the magnetic induction.

There is a magnetic field around the current (moving charge), and his important manifestation is that it has the effect of magnetic field force on the motion tentative charge, current-carrying conductor or permanent magnet introduced into the field, so the magnetic field can be described by the effect of the magnetic field on the motion tentative charge, and thus the magnetic induction intensity b is introduced as the basic physical quantity to quantitatively describe the characteristics of each point in the magnetic field, and its position is the same as the electric field strength in the electric field.

e quite. This physical quantity is called thatMagnetic Induction Intensity:, and not calledMagnetic field strength

Difference: The magnetic induction intensity reflects the interaction force, which is the stress relationship between the two reference points A and B, while the magnetic field strength is the unilateral quantity of the subject, regardless of whether the B side participates or not, this quantity is invariant.

The difference between the strength of magnetic induction and the strength of the magnetic field:

First, the meaning is different:

1. The meaning of magnetic induction intensity: Magnetic induction intensity refers to the physical quantity that describes the strength and direction of the magnetic field, which is a vector quantity, and is commonly represented by the symbol B. Magnetic induction intensity is also known as magnetic flux density or magnetic flux density.

2. The meaning of magnetic field strength: The magnetic field strength was first introduced from the magnetic charge point of view in history. Analogous to Coulomb's law of electric charge, it is believed that there are two kinds of magnetic charges, positive and negative, and Coulomb's law of magnetic charge is proposed. The force exerted on the unit positive magnetic charge in the magnetic field is known as the magnetic field strength h.

Second, the units of the two are different:

1. The unit of magnetic induction intensity: the international unit is Tesla (the symbol is t).

2. The unit of magnetic field strength: ampere meters.

3. The calculation formulas of the two are different:

1. The calculation formula of magnetic induction intensity: the point charge q is affected by the force f when it moves in the magnetic field with velocity v. Under the given conditions of a magnetic field, the magnitude of f is related to the direction of the charge motion.

When v is in a particular direction or opposite to it, the force is zero; When v is perpendicular to this particular direction, the force is maximum, which is fm.

fm with |q|and v is proportional, the ratio has nothing to do with the moving charge, reflects the nature of the magnetic field itself, and is defined as the magnitude of the magnetic induction intensity, ie. The direction of b is defined as the direction in which the right hand spirals forward when the direction of the maximum force fm of the positive charge is turned to the direction of the charge motion v.

After defining b, the force exerted on the moving charge in the magnetic field b can be expressed as f= qvb, which is the Lorentz force formula.

2. Calculation formula of magnetic field strength: magnetic field strength describes the physical quantity of magnetic field properties. It is defined as h=b 0-m, where b is the magnetic induction, m is the magnetization, 0 is the permeability in a vacuum, and 0=4 10-7 Weber (m·ampere).

The unit of h is Am. In the Gaussian system of units, the unit of h is Oersted. 1 m = 4 10-3 Oersted.