The magnetic flux is measured with this conductor loop and the voltage induced in it. The magnetic flux is equal to the time integral over this surge: If a conductor loop with a known area is brought into a magnetic field, this indicates a surge there. If the direction of the current were reversed, the poles would be reversed.įrom a physical point of view, the magnetic flux is therefore defined by the inductive effect that it exerts on a conductor loop. The circular current creates a so-called magnetic moment with the south pole below the conductor loop and the north pole above this conductor loop. They are responsible for the magnetic flux or the magnetic field. It is important to understand that permanent magnets are also based on this behavior with regard to the magnetic flux density: microscopic circular currents with a current I, are formed there, caused by movements of the electrons in the material. The Maxwell equations from electrodynamics express this fact mathematically. This fact is the reason why two poles always form a magnet: a south pole and a north pole.
Physically correct, this means that there are no sources and no sinks in the magnetic flux or the magnetic flux density. This has no beginning and no end, because currents only create closed field lines. The area must be perpendicular to the flux. The magnetic flux therefore results from a certain area A to the product with the magnetic flux density B. The magnetic flux itself has the formula symbol Φ and basically denotes the entirety of all magnetic field lines. The flux density of a magnet therefore continues to run in its exterior. The density of the field lines in a cross section is so to say the magnetic flux density.Īccording to the so-called Maxwell equations - a very well-known physical law in electrodynamics - field lines cannot simply stop. It is helpful to imagine an image with the magnetic field lines between two poles. The magnetic flux density that runs through an imaginary surface is the magnetic flux.
magnetic flux – Is there a difference here? There are numerous formulas for performing this calculation. B describes the density of the magnetic flux through a surface.
Sometimes it is also called magnetic induction. The magnetic flux density B in turn indicates how strong this magnetic field actually is. This would exert forces on nearby cobalt, nickel, iron or other ferromagnetic materials. The descriptive explanation of the physical background should help a little: A so-called magnetic field is formed around a conductor through which electricity flows. Many cannot really use the magnetic flux density formula mentioned above. The product of the two permeability constants and the magnetic field H thus by definition gives the magnetic flux density B. If it is again a superconductor, then μ = 0.In the case of ferromagnetic materials, this value can sometimes go up to 100,000.As long as the material is not ferromagnetic, the material-specific permeability constant μ about 1.The following relationship applies with the so-called permeability constants μ0 (for vacuum) and μ (for additional materials): The permeability constant can vary depending on the type of material: While by definition the magnetic flux density is described by the letter B the letter for the magnetic field is H. The designation B-field is wanted: it is not the actual magnetic field, even if the two terms are sometimes used interchangeably in the literature. As a so-called B field, it is an indirect measure of the strength of a magnetic field. Nevertheless, again due to the symmetry, this influence will be equal to zero in vertical symmetry plane.The magnetic flux density is defined as the density of the field lines. There is still a problem with "vertical" parts of the yoke, they will distort the uniformity of the field within the working area. take two identical permanent magnets with diameters equal or bigger than the distance between their near, attracting poles. To make your working area filled with uniform field just imitate Helmholtz coils arrangement, i.e. It's quite likely that room temperature variations may influence the field between permanent magnets even more. Yoke's field will then slightly decrease the field between permanent magnets. You may think of this magnet as of the iron yoke in your apparatus. Moreover, this field is directed oppositely to the one inside the magnet. On the other hand, the B (or H) lines are always closed, hence the weak field is present near magnet's sides. The strongest field it creates is, of course, near its poles.
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